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1
Youssef, Irini, Jennifer Yoon, Nader Mohamed, Kaveh Zakeri, Robert H. Press, Linda Chen, Daphna Y. Gelblum, et al. "Toxicity Profiles and Survival Outcomes Among Patients With Nonmetastatic Oropharyngeal Carcinoma Treated With Intensity-Modulated Proton Therapy vs Intensity-Modulated Radiation Therapy." JAMA Network Open 5, no. 11 (November 11, 2022): e2241538. http://dx.doi.org/10.1001/jamanetworkopen.2022.41538.
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ImportancePatients with oropharyngeal carcinoma (OPC) treated with radiotherapy often experience substantial toxic effects, even with modern techniques such as intensity-modulated radiation therapy (IMRT). Intensity-modulated proton therapy (IMPT) has a potential advantage over IMRT due to reduced dose to the surrounding organs at risk; however, data are scarce given the limited availability and use of IMPT.ObjectiveTo compare toxic effects and oncologic outcomes among patients with newly diagnosed nonmetastatic OPC treated with IMPT vs IMRT with or without chemotherapy.Design, Setting, and ParticipantsThis retrospective cohort study included patients aged 18 years or older with newly diagnosed nonmetastatic OPC who received curative-intent radiotherapy with IMPT or IMRT at a single-institution tertiary academic cancer center from January 1, 2018, to December 31, 2021, with follow-up through December 31, 2021.ExposuresIMPT or IMRT with or without chemotherapy.Main Outcomes and MeasuresThe main outcomes were the incidence of acute and chronic (present after ≥6 months) treatment-related adverse events (AEs) and oncologic outcomes, including locoregional recurrence (LRR), progression-free survival (PFS), and overall survival (OS). Fisher exact tests and χ2 tests were used to evaluate associations between toxic effects and treatment modality (IMPT vs IMRT), and the Kaplan-Meier method was used to compare LRR, PFS, and OS between the 2 groups.ResultsThe study included 292 patients with OPC (272 [93%] with human papillomavirus [HPV]-p16–positive tumors); 254 (87%) were men, 38 (13%) were women, and the median age was 64 years (IQR, 58-71 years). Fifty-eight patients (20%) were treated with IMPT, and 234 (80%) were treated with IMRT. Median follow-up was 26 months (IQR, 17-36 months). Most patients (283 [97%]) received a dose to the primary tumor of 70 Gy. Fifty-seven of the patients treated with IMPT (98%) and 215 of those treated with IMRT (92%) had HPV-p16–positive disease. There were no significant differences in 3-year OS (97% IMPT vs 91% IMRT; P = .18), PFS (82% IMPT vs 85% IMRT; P = .62), or LRR (5% IMPT vs 4% IMRT; P = .59). The incidence of acute toxic effects was significantly higher for IMRT compared with IMPT for oral pain of grade 2 or greater (42 [72%] IMPT vs 217 [93%] IMRT; P < .001), xerostomia of grade 2 or greater (12 [21%] IMPT vs 68 [29%] IMRT; P < .001), dysgeusia of grade 2 or greater (16 [28%] IMPT vs 134 [57%] IMRT; P < .001), grade 3 dysphagia (4 [7%] IMPT vs 29 [12%] IMRT; P < .001), mucositis of grade 3 or greater (10 [53%] IMPT vs 13 [70%] IMRT; P = .003), nausea of grade 2 or greater (0 [0%] IMPT vs 18 [8%] IMRT; P = .04), and weight loss of grade 2 or greater (22 [37%] IMPT vs 138 [59%] IMRT; P < .001). There were no significant differences in chronic toxic effects of grade 3 or greater, although there was a significant difference for chronic xerostomia of grade 2 or greater (6 IMPT [11%] vs 22 IMRT [10%]; P < .001). Four patients receiving IMRT (2%) vs 0 receiving IMPT had a percutaneous endoscopic gastrostomy tube for longer than 6 months.Conclusions and RelevanceIn this study, curative-intent radiotherapy with IMPT for nonmetastatic OPC was associated with a significantly reduced acute toxicity burden compared with IMRT, with few chronic toxic effects and favorable oncologic outcomes, including locoregional recurrence of only 5% at 2 years. Prospective randomized clinical trials comparing these 2 technologies and of patient-reported outcomes are warranted.
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Thaker, Nikhil G., David Boyce-Fappiano, Matthew S. Ning, Dario Pasalic, Alexis Guzman, Grace Smith, Emma B. Holliday, et al. "Activity-Based Costing of Intensity-Modulated Proton versus Photon Therapy for Oropharyngeal Cancer." International Journal of Particle Therapy 8, no. 1 (June 1, 2021): 374–82. http://dx.doi.org/10.14338/ijpt-20-00042.1.
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Abstract Purpose In value-based health care delivery, radiation oncologists need to compare empiric costs of care delivery with advanced technologies, such as intensity-modulated proton therapy (IMPT) and intensity-modulated radiation therapy (IMRT). We used time-driven activity-based costing (TDABC) to compare the costs of delivering IMPT and IMRT in a case-matched pilot study of patients with newly diagnosed oropharyngeal (OPC) cancer. Materials and Methods We used clinicopathologic factors to match 25 patients with OPC who received IMPT in 2011-12 with 25 patients with OPC treated with IMRT in 2000-09. Process maps were created for each multidisciplinary clinical activity (including chemotherapy and ancillary services) from initial consultation through 1 month of follow-up. Resource costs and times were determined for each activity. Each patient-specific activity was linked with a process map and TDABC over the full cycle of care. All calculated costs were normalized to the lowest-cost IMRT patient. Results TDABC costs for IMRT were 1.00 to 3.33 times that of the lowest-cost IMRT patient (mean ± SD: 1.65 ± 0.56), while costs for IMPT were 1.88 to 4.32 times that of the lowest-cost IMRT patient (2.58 ± 0.39) (P < .05). Although single-fraction costs were 2.79 times higher for IMPT than for IMRT (owing to higher equipment costs), average full cycle cost of IMPT was 1.53 times higher than IMRT, suggesting that the initial cost increase is partly mitigated by reductions in costs for other, non-RT supportive health care services. Conclusions In this matched sample, although IMPT was on average more costly than IMRT primarily owing to higher equipment costs, a subset of IMRT patients had similar costs to IMPT patients, owing to greater use of supportive care resources. Multidimensional patient outcomes and TDABC provide vital methodology for defining the value of radiation therapy modalities.
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Yoon, Han Gyul, Yong Chan Ahn, Dongryul Oh, Jae Myoung Noh, Seung Gyu Park, Heerim Nam, Sang Gyu Ju, Dongyeol Kwon, and Seyjoon Park. "Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients." Cancers 13, no. 7 (March 27, 2021): 1549. http://dx.doi.org/10.3390/cancers13071549.
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Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and intensity-modulated proton therapy (IMPT) in comparison with IMRT alone in treating oropharynx cancer (OPC) patients. Materials and Methods: The medical records of 148 OPC patients who underwent definitive radiotherapy (RT) with concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During the 5.5 weeks’ RT course, the initial 16 (or 18) fractions were delivered by IMRT in all patients, and the subsequent 12 (or 10) fractions were either by IMRT in 81 patients (IMRT only) or by IMPT in 67 (IMRT/IMPT combination), respectively, based on comparison of adaptive re-plan profiles and availability of equipment. Propensity-score matching (PSM) was done on 76 patients (38 from each group) for comparative analyses. Results: With the median follow-up of 24.7 months, there was no significant difference in overall survival and progression free survival between groups, both before and after PSM. Before PSM, the IMRT/IMPT combination group experienced grade ≥ 3 acute toxicities less frequently: mucositis in 37.0% and 13.4% (p < 0.001); and analgesic quantification algorithm (AQA) in 37.0% and 19.4% (p = 0.019), respectively. The same trends were observed after PSM: mucositis in 39.5% and 15.8% (p = 0.021); and AQA in 47.4% and 21.1% (p = 0.016), respectively. In multivariate logistic regression, grade ≥ 3 mucositis was significantly less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.027 and 0.024, respectively). AQA score ≥ 3 was also less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.085 and 0.018, respectively). Conclusions: In treating the OPC patients, with comparable early oncologic outcomes, more favorable acute toxicity profiles were achieved following IMRT/IMPT combination than IMRT alone.
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Nenoff, Lena, Atchar Sudhyadhom, Jackson Lau, Gregory C. Sharp, Harald Paganetti, and Jennifer Pursley. "Comparing Predicted Toxicities between Hypofractionated Proton and Photon Radiotherapy of Liver Cancer Patients with Different Adaptive Schemes." Cancers 15, no. 18 (September 15, 2023): 4592. http://dx.doi.org/10.3390/cancers15184592.
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With the availability of MRI linacs, online adaptive intensity modulated radiotherapy (IMRT) has become a treatment option for liver cancer patients, often combined with hypofractionation. Intensity modulated proton therapy (IMPT) has the potential to reduce the dose to healthy tissue, but it is particularly sensitive to changes in the beam path and might therefore benefit from online adaptation. This study compares the normal tissue complication probabilities (NTCPs) for liver and duodenal toxicity for adaptive and non-adaptive IMRT and IMPT treatments of liver cancer patients. Adaptive and non-adaptive IMRT and IMPT plans were optimized to 50 Gy (RBE = 1.1 for IMPT) in five fractions for 10 liver cancer patients, using the original MRI linac images and physician-drawn structures. Three liver NTCP models were used to predict radiation-induced liver disease, an increase in albumin-bilirubin level, and a Child–Pugh score increase of more than 2. Additionally, three duodenal NTCP models were used to predict gastric bleeding, gastrointestinal (GI) toxicity with grades >3, and duodenal toxicity grades 2–4. NTCPs were calculated for adaptive and non-adaptive IMRT and IMPT treatments. In general, IMRT showed higher NTCP values than IMPT and the differences were often significant. However, the differences between adaptive and non-adaptive treatment schemes were not significant, indicating that the NTCP benefit of adaptive treatment regimens is expected to be smaller than the expected difference between IMRT and IMPT.
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Cunningham, Lisa, Scott Penfold, Eileen Giles, Hien Le, and Michala Short. "Impact of Breast Size on Dosimetric Indices in Proton Versus X-ray Radiotherapy for Breast Cancer." Journal of Personalized Medicine 11, no. 4 (April 8, 2021): 282. http://dx.doi.org/10.3390/jpm11040282.
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Deep inspiration breath hold (DIBH) radiotherapy is a technique used to manage early stage left-sided breast cancer. This study compared dosimetric indices of patient-specific X-ray versus proton therapy DIBH plans to explore differences in target coverage, radiation doses to organs at risk, and the impact of breast size. Radiotherapy plans of sixteen breast cancer patients previously treated with DIBH radiotherapy were re-planned with hybrid inverse-planned intensity modulated X-ray radiotherapy (h-IMRT) and intensity modulated proton therapy (IMPT). The total prescribed dose was 40.05 Gy in 15 fractions for all cases. Comparisons between the clinical, h-IMRT, and IMPT evaluated doses to target volumes, organs at risk, and correlations between doses and breast size. Although no differences were observed in target volume coverage between techniques, the h-IMRT and IMPT were able to produce more even dose distributions and IMPT delivered significantly less dose to all organs at risk than both X-ray techniques. A moderate negative correlation was observed between breast size and dose to the target in X-ray techniques, but not IMPT. Both h-IMRT and IMPT produced plans with more homogeneous dose distribution than forward-planned IMRT and IMPT achieved significantly lower doses to organs at risk compared to X-ray techniques.
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Lescut, Nicolas, Etienne Martin, Philippe Maingon, Magali Quivrin, Celine Mirjolet, Suzanne Naudy, Aurelie Petitfils, and Gilles Crehange. "Dependence of intrafraction prostate motion within the pelvis on fraction duration during whole pelvic intensity modulated arctherapy (IMAT) versus dynamic IMRT." Journal of Clinical Oncology 31, no. 6_suppl (February 20, 2013): 190. http://dx.doi.org/10.1200/jco.2013.31.6_suppl.190.
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190 Background: To compare the 3-dimensional intra-fraction variations of prostate position within the pelvis with whole-pelvic fixed-field intensity-modulated radiation therapy (IMRT) vs. intensity-modulated arc therapy (IMAT) in high-risk prostate cancer. Methods: Fifteen PCa patients underwent whole pelvic radiotherapy using either dynamic IMRT with a sliding window technique (n= 8) or IMAT (n= 7). All the patients had a kV cone-beam computed tomography (CBCT) before and immediately after each fraction of IMRT or IMAT. Intra-fraction motions of the prostate were determined using a 2-step procedure performed on each pre- and post-treatment imaging: 1) planning CT and CBCT were matched on bony structures after automatic semi-rigid fusion alongside the 3 axis (x, y, z), 2) planning CT and CBCT were matched on the prostate with respect to intra-prostatic markers: xsoft, ysoft, zsoft. The position of the prostate within the pelvis for each pre- and post-treatment study points was defined as xpros= (xbone – xsoft), ypros= (ybone – ysoft) and zpros= (zbone – zsoft). Rectum and bladder were outlined on each CBCT with the aim to assess changes in rectal or vesical repletion during each fraction. Organ distension was assessed by measuring the average rectal cross-sectional area (rCSA; defined as the rectal volume divided by length), and the area of the bladder when evaluated 2.5cm above the prostate base (A-blad) on pre- and post-treatment CBCT. Results: Two hundred and ninety four CBCT were reviewed for this analysis. The average fraction duration was shorter with IMAT than with IMRT (4’49’’, vs. 11’00’’, p< 0.001). During fractions of IMRT the prostate showed statistically significant shifts in the longitudinal (p= 0,049) and lateral (p=0,013) axis while it was not statistically significant during fractions of IMAT. Intra-fraction rCSA increased neither during IMAT nor IMRT whereas A-blad increased only during fractions of IMRT but with no correlation with prostate displacements. Conclusions: The prostate moves within the pelvis during an IMRT course which could lead to a greater daily geographic miss when compared to the IMAT technique.
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Jain, Varsha, Peyton Irmen, Shannon O'Reilly, Jennifer H. Vogel, Liyong Lin, and Alexander Lin. "Predicted Secondary Malignancies following Proton versus Photon Radiation for Oropharyngeal Cancers." International Journal of Particle Therapy 6, no. 4 (March 1, 2020): 1–10. http://dx.doi.org/10.14338/ijpt-19-00076.1.
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Abstract Purpose There has been a recent epidemic of human papillomavirus (HPV)–positive oropharyngeal cancer, accounting for 70% to 80% of diagnosed cases. These patients have an overall favorable prognosis and are typically treated with a combination of surgery, chemotherapy, and radiation. Because these patients live longer, they are at risk of secondary malignant neoplasms (SMNs) associated with radiation therapy. Therefore, we assessed the predicted risk of SMNs after adjuvant radiation therapy with intensity-modulated proton therapy (IMPT) compared with intensity modulated photon radiation therapy (IMRT) in patients with HPV- positive oropharyngeal cancers after complete resection. Materials and Methods Thirteen consecutive patients with HPV-positive oropharyngeal cancers treated with postoperative radiation alone were selected. All patients were treated with pencil beam scanning IMPT to a total dose of 60 Gy in 2 Gy fractions. The IMRT plans were generated for clinical backup and were used for comparative purposes. The SMN risk was calculated based on an organ equivalent dose model for the linear-exponential dose-response curve. Results Median age of the patient cohort was 63 years (range, 47-73 years). There was no difference in target coverage between IMPT and IMRT plans. We noted significant reductions in mean mandible, contralateral parotid, lung and skin organ equivalent doses with IMPT compared with IMRT plans (P < .001). Additionally, a significant decrease in the risk of SMNs with IMPT was observed for all the evaluated organs. Per our analysis, for patients with oropharyngeal cancers diagnosed at a national median age of 54 years with an average life expectancy of 27 years (per national Social Security data), 4 excess SMNs per 100 patients could be avoided by treating them with IMPT versus IMRT. Conclusions Treatment with IMPT can achieve comparable target dose coverage while significantly reducing the dose to healthy organs, which can lead to fewer predicted SMNs compared with IMRT.
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Patrice Aka, Fleman, Roger Taylor, Richard Hugtenburg, Jamil Lambert, and James Powell. "Hippocampal sparing radiotherapy in adults with primary brain tumours: a comparative planning and dosimetric study using IMPT, IMRT and 3DCRT." Neuro-Oncology 21, Supplement_4 (October 2019): iv2—iv3. http://dx.doi.org/10.1093/neuonc/noz167.008.
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Abstract Introduction We assessed the feasibility of hippocampal sparing in adults with primary brain tumours using Intensity Modulated Proton Therapy (IMPT) and compared this with Intensity Modulated Radiotherapy (IMRT) and 3D-Conformal Radiotherapy (3DCRT). Methods and Materials 20 patients were identified, and each patient underwent a radiotherapy planning CT scan and 2 MRI scans. A pre-operative diagnostic MRI scan was fused with the planning CT and used for target delineation and a dedicated 3T MRI scan at the time of planning was fused with the CT for hippocampus delineation. 3 hippocampal sparing plans were generated for each patient with specific prescriptions (54Gy/30 fractions, 60Gy/30 fractions and 59.4Gy/33 fractions) using IMPT, IMRT and 3DCRT. Hippocampal sparing was defined as median dose to contralateral hippocampus ≤25Gy without compromising target coverage and organ at risk dose constraints. Results Hippocampal sparing was achieved in 19 patients (95%) with IMPT, 16 patients (80%) with IMRT and 13 patients (65%) with 3DCRT. The largest median hippocampal dose reduction was seen with IMPT, with a mean median hippocampal dose of 4.8Gy (range: 0.0Gy-24.9Gy), 14.6Gy (range: 1.9Gy-21.7Gy), and 16.2Gy (range: 2.3Gy-25.0Gy) for IMPT, IMRT and 3DCRT respectively. Hippocampal sparing IMPT failed in one case with the largest tumour volume (650cc) where 2/3 of the hippocampus overlapped the target volume. Conclusion IMPT as compared to IMRT and 3DCRT plans showed a trend towards significant and effective hippocampal sparing in adult patients with primary brain tumours. We are currently evaluating this in a larger patient cohort and comparing IMPT with VMAT.
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Wong, Ru Xin, Jacqueline Faught, Melissa Gargone, William Myers, Matthew Krasin, Austin Faught, and Sahaja Acharya. "Cardiac-Sparing and Breast-Sparing Whole Lung Irradiation Using Intensity-Modulated Proton Therapy." International Journal of Particle Therapy 7, no. 4 (March 1, 2021): 65–73. http://dx.doi.org/10.14338/ijpt-20-00079.1.
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Abstract Purpose Whole lung irradiation (WLI) is indicated for certain pediatric patients with lung metastases. This study investigated whether WLI delivered as intensity-modulated proton therapy (IMPT) could significantly spare the heart and breasts when compared with conventional WLI delivered with anteroposterior/posteroanterior photon fields and with intensity-modulated photon therapy (IMRT) WLI. Materials and Methods Conventional, IMRT, and IMPT plans were generated for 5 patients (aged 5-22 years). The prescription dose was 16.5 GyRBE in 1.5-GyRBE fractions. Conventional plans used 6-MV photons prescribed to the midline and a field-in-field technique to cover the planning target volume (the internal target volume [ITV] + 1 cm). IMRT plans used 6-MV photons with a 7-beam arrangement with dose prescribed to the planning target volume. IMPT plans used scenario-based optimization with 5% range uncertainty and 5-mm positional uncertainty to cover the ITV robustly. Monte Carlo dose calculation was used for all IMPT plans. Doses were compared with paired Student t test. Results The ITV Dmean was similar for the IMPT, conventional, and IMRT plans, but the IMPT plans had a lower Dmin and a higher Dmax at tissue interfaces than conventional plans (Dmean ratio: 0.96, P > .05; Dmin ratio: 0.9, P < .001; Dmax ratio: 1.1, P = .014). Dmeans for breast and heart substructures were lower with IMPT plans than with conventional/IMRT plans (heart ratios, 0.63:0.73; left ventricle ratios, 0.61:0.72; right ventricle ratios, 0.45:0.57; left atrium ratios, 0.79:0.85; right atrium ratios, 0.81:0.86; left breast ratios, 0.40:0.51; right breast ratio, 0.46:0.52; all P < .05). Conclusions IMPT resulted in comparable ITV coverage and lower mean doses to the heart and breasts when compared with other techniques. Whole lung irradiation delivered as IMPT warrants prospective evaluation in pediatric patients.
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Vernanda, V., A. Azzi, and S. A. Pawiro. "Dose Planning Evaluation of Intensity-Modulated Proton Therapy (IMPT) Technique Based on In-House Dynamic Thorax Phantom." Atom Indonesia 1, no. 1 (March 24, 2023): 7–11. http://dx.doi.org/10.55981/aij.2023.1196.
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One of the drawbacks of the Intensity Modulated Radiation Therapy (IMRT) technique is that the absorbed dose in healthy tissue is relatively high. Proton beam has characteristics that can compensate for these drawbacks. The Bragg peak characteristic of a proton beam allows the administration of high radiation doses to the target organ only. Non-Small Cell Lung Cancer (NSCLC) cases are located in the vicinity of many vital organs, so radiation doses that exceed a certain limit will have a significant impact on these organs. Proton is a heavy particle that exhibits interaction patterns with tissue heterogeneity that differ from that of photon. This study aims to determine the distribution of proton beam planning doses in the NSCLC cases with the Intensity Modulated Proton Therapy (IMPT) technique and compare its effectiveness with the IMRT technique. Treatment planning was done by using TPS Eclipse on the water phantom and on the in-house thorax dynamic phantom. The water phantom planning parameters used are one field at 0° and three fields at 45°, 135°, and 225°. In this study, a single, sum, and multiple field techniques on the in-house thorax dynamic phantom were used. The evaluation was performed by calculating Conformity Index (CI), Homogeneity Index (HI), and Gradient Index (GI) parameters for each treatment planning. As a result, a bit of difference in the CI the HI values are shown between IMPT and IMRT planning. The GI values of IMPT planning are in the range between 4.15-4.53, while the GI value of IMRT is 7.89. The histogram results of the planar dose distribution show that the IMPT treatment planning provides fewer off-target organ doses than the IMRT planning. Evaluation was also carried out on the IMPT treatment planning of target organs in five areas of interest and four OAR positions. The evaluation results were then compared with the IMRT measurement data. As a result, the value of the point doses at the target organ did not differ significantly. However, the absorbed dose with the IMPT technique at four OAR positions is nearly zero, which had a large difference compared to the IMRT technique.
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Gogineni, Emile, Hao Chen, Alexandra C. Istl, Fabian M. Johnston, Amol Narang, and Curtiland Deville. "Comparative In Silico Analysis of Ultra-Hypofractionated Intensity-Modulated Photon Radiotherapy (IMRT) Versus Intensity-Modulated Proton Therapy (IMPT) in the Pre-Operative Treatment of Retroperitoneal Sarcoma." Cancers 15, no. 13 (July 4, 2023): 3482. http://dx.doi.org/10.3390/cancers15133482.
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Background: While pre-operative radiation did not improve abdominal recurrence-free survival for retroperitoneal sarcoma (RPS) in the randomized STRASS trial, it did reduce rates of local recurrence. However, the risk of toxicity was substantial and the time to surgery was prolonged. A combination of hypofractionation and proton therapy may reduce delays from the initiation of radiation to surgery and limit the dose to surrounding organs at risk (OARs). We conducted a dosimetric comparison of the pre-operative ultra-hypofractionated intensity-modulated photon (IMRT) and proton radiotherapy (IMPT). Methods: Pre-operative IMRT and IMPT plans were generated on 10 RPS patients. The prescription was 25 Gy radiobiological equivalents (GyEs) (radiobiological effective dose of 1.1) to the clinical target volume and 30 GyEs to the margin at risk, all in five fractions. Comparisons were made using student T-tests. Results: The following endpoints were significantly lower with IMPT than with IMRT: mean doses to liver, bone, and all genitourinary and gastrointestinal OARs; bowel, kidney, and bone V5–V20; stomach V15; liver V5; maximum doses to stomach, spinal canal, and body; and whole-body integral dose. Conclusions: IMPT maintained target coverage while significantly reducing the dose to adjacent OARs and integral dose compared to IMRT. A prospective trial treating RPS with pre-operative ultra-hypofractionated IMPT at our institution is currently being pursued.
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Smith, Grace L., Shuangshuang Fu, Matthew S. Ning, Diem-Khanh Nguyen, Paul M. Busse, Robert L. Foote, Adam S. Garden, et al. "Work Outcomes after Intensity-Modulated Proton Therapy (IMPT) versus Intensity-Modulated Photon Therapy (IMRT) for Oropharyngeal Cancer." International Journal of Particle Therapy 8, no. 1 (June 1, 2021): 319–27. http://dx.doi.org/10.14338/ijpt-20-00067.1.
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Abstract Purpose We compared work outcomes in patients with oropharyngeal cancer (OPC), randomized to intensity-modulated proton (IMPT) versus intensity-modulated photon therapy (IMRT) for chemoradiation therapy (CRT). Patients and Methods In 147 patients with stage II-IVB squamous cell OPC participating in patient-reported outcomes assessments, a prespecified secondary aim of a randomized phase II/III trial of IMPT (n = 69) versus IMRT (n = 78), we compared absenteeism, presenteeism (i.e., the extent to which an employee is not fully functional at work), and work productivity losses. We used the work productivity and activity impairment questionnaire at baseline (pre-CRT), at the end of CRT, and at 6 months, 1 year, and 2 years. A one-sided Cochran-Armitage test was used to analyze within-arm temporal trends, and a χ2 test was used to compare between-arm differences. Among working patients, at each follow-up point, a 1-sided Wilcoxon rank-sum test was used to compare work-productivity scores. Results Patient characteristics in IMPT versus IMRT arms were similar. In the IMPT arm, within-arm analysis demonstrated that an increasing proportion of patients resumed working after IMPT, from 60% (40 of 67) pre-CRT and 71% (30 of 42) at 1 year to 78% (18 of 23) at 2 years (P = 0.025). In the IMRT arm, the proportion remained stable, with 57% (43 of 76) pre-CRT, 54% (21 of 39) at 1 year, and 52% (13 of 25) working at 2 years (P = 0.47). By 2 years after CRT, the between-arm difference between patients who had IMPT and those who had IMRT trended toward significance (P = 0.06). Regardless of treatment arm, among working patients, the most severe work impairments occurred from treatment initiation to the end of CRT, with significant recovery from absenteeism, presenteeism, and productivity impairments by the 2-year follow-up (P < 0.001 for all). Higher magnitudes of recovery from absenteeism (at 1 year, P = 0.05; and at 2 years, P = 0.04) and composite work impairment scores (at 1 year, P = 0.04; and at 2 years, P = 0.04) were seen in patients treated with IMPT versus those treated with IMRT. Conclusion In patients with OPC receiving curative CRT, patients randomized to IMPT demonstrated increasing work and productivity recovery trends. Studies are needed to identify mechanisms underlying head and neck CRT treatment causing work disability and impairment.
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Lin, Ruihe, Jie Shan, Taize Yuan, and Chaonan Qian. "Dosimetric comparison of intensity-modulated proton radiotherapy versus intensity-modulated photon-based radiotherapy for breast cancer." Visualized Cancer Medicine 2 (2021): 5. http://dx.doi.org/10.1051/vcm/2021002.
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Purpose: This study aims to compare the dosimetric differences in intensity-modulated proton therapy (IMPT) using pencil beam scanning technology and intensity-modulated photon-based radiotherapy (IMRT) in hypofractionated whole-breast irradiation (HF-WBI) and find out the more beneficial technique. Methods and Materials: Eight breast cancer (BC) patients with pathological stage T1 ~ 2N0M0 were immobilized and underwent 4D-CT scanning used deep inspiration breath-hold (DIBH) technology. The IMPT and IMRT plans were designed for each patient. The IMPT plans used two en-face beam angles. IMRT plans were designed using the field in field technique. The optimization constraints of the two types of plans were identical. Prescription dose and regimen was 40.05 Gy (relative biological effect [RBE])/15 fx with a 10 Gy (RBE)/5 fx boost, five fractions a week. A dose of 95% of the target volume should not be less than the prescribed dose. The target coverage was evaluated using D1, D2, D50, D95, D98, and D99. The target dose distribution and conformity were evaluated using the Conformity index (CI) and the homogeneity index (HI). The Organs at risk (OARs) were evaluated using mean dose (Dmean) and maximum dose (Dmax). Ipsilateral Lung and Contralateral Lung were evaluated additionally using V5, V10, V20, V30. Results: The mean dose (Dmean) of the Heart (P = 0.012), Ipsilateral Lung (P = 0.036), Contralateral Lung (P = 0.012), and Spinal Cord (P = 0.012) were significantly reduced in IMPT plans. The IMPT also showed a tendency to reduce the V20 (P = 0.05) and V30 (P = 0.05) of the Ipsilateral Lung. But there was no significant difference in target coverage, homogeneity, and conformity between the IMRT and IMPT plans. Conclusion: Compared to IMRT, the IMPT using pencil beam scanning technology can spare OARs without compromising target coverage in BC patients undergoing HF-WBI, which potentially reduce the incidence of radiation-related adverse effects and thus may positively impact long-term survival.
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Corbeau, Anouk, Remi A. Nout, Jan Willem M. Mens, Nanda Horeweg, Jérémy Godart, Ellen M. Kerkhof, Sander C. Kuipers, et al. "PROTECT: Prospective Phase-II-Trial Evaluating Adaptive Proton Therapy for Cervical Cancer to Reduce the Impact on Morbidity and the Immune System." Cancers 13, no. 20 (October 15, 2021): 5179. http://dx.doi.org/10.3390/cancers13205179.
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External beam radiation therapy (EBRT) with concurrent chemotherapy followed by brachytherapy is a very effective treatment for locally advanced cervical cancer (LACC). However, treatment-related toxicity is common and reduces the patient’s quality of life (QoL) and ability to complete treatment or undergo adjuvant therapies. Intensity modulated proton therapy (IMPT) enables a significant dose reduction in organs at risk (OAR), when compared to that of standard intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). However, clinical studies evaluating whether IMPT consequently reduces side effects for LACC are lacking. The PROTECT trial is a nonrandomized prospective multicenter phase-II-trial comparing clinical outcomes after IMPT or IMRT/VMAT in LACC. Thirty women aged >18 years with a histological diagnosis of LACC will be included in either the IMPT or IMRT/VMAT group. Treatment includes EBRT (45 Gy in 25 fractions of 1.8 Gy), concurrent five weekly cisplatin (40 mg/m2), and 3D image (MRI)-guided adaptive brachytherapy. The primary endpoint is pelvic bones Dmean and mean bowel V15Gy. Secondary endpoints include dosimetric parameters, oncological outcomes, health-related QoL, immune response, safety, and tolerability. This study provides the first data on the potential of IMPT to reduce OAR dose in clinical practice and improve toxicity and QoL for patients with LACC.
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Wilkens, J. "THE IMRT/IMPT OPTIMIZATION PROBLEM." Radiotherapy and Oncology 92 (August 2009): S10. http://dx.doi.org/10.1016/s0167-8140(12)72609-9.
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Nguyen, Tu Thi Cam, Nhon Van Mai, and Binh Thai Nguyen. "Comparison of intensity modulated photon therapy and intensity modulated proton therapy plans for prostate cancer." Science and Technology Development Journal 18, no. 3 (August 30, 2015): 93–100. http://dx.doi.org/10.32508/stdj.v18i3.825.
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Nowadays, traditional radiation therapy using x-rays is still the most common type of external exposure in curing cancer. However, the persisting problem is that significant dose delivered to normal tissues because of the characteristics of interaction of photons with matter even with the most advanced delivery techniques such as IMRT, IGRT, etc. Proton therapy is not only the technique producing better conformity to target but also better sparing to organs at risk. In this work, intensity modulated proton therapy (IMPT) and intensity modulated photon therapy (IMRT) plans are generated for a prostate patient. The evaluation and comparison of the two treatment plans were performed in term of physical quantity based on Dose Volume Histogram (DVH) and dose statistics for both target and organs at risk. The results of our study show that IMPT could be beneficial compared to IMRT with 5 fields. The doses to intestine and bladder are low resulting in possibly reducing side effects and second malignancies
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Alterio, Daniela, Simona Marani, Valeria Zurlo, Stefano Filippo Zorzi, Annamaria Ferrari, Stefania Volpe, Francesco Bandi, et al. "Intensity-Modulated Radiotherapy (IMRT) following Conservative Surgery of the Supraglottic Region: Impact on Functional Outcomes." Cancers 14, no. 11 (May 24, 2022): 2600. http://dx.doi.org/10.3390/cancers14112600.
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The aim of the present study was to investigate the role of intensity-modulated radiotherapy (IMRT) on the toxicity profile of patients treated with conservative surgery (CS) of the supraglottic (SG) region. Data on patients treated with CS and postoperative radiotherapy (PORT)-IMRT were prospectively collected. Results. In total, 20 patients were analyzed. Of these, six patients (35%) required the positioning of a temporary tracheostomy. The functional larynx preservation rate was 95%. Females had a higher risk of both endoscopic intervention and chondronecrosis, while the median age was significantly higher in patients requiring enteral nutrition. The incidence of long-term severe toxicities was lower in patients treated with IMRT than in the historical 3D-CRT cohort. Patients who had received PORT-IMRT achieved a lower rate of permanent laryngeal and swallowing dysfunctions. Overall, results from the comparison with the historical 3D-CRT cohort favor the IMRTs.
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De Felice, Francesca, Alessandro Vai, Anna Maria Camarda, Nicola Alessandro Iacovelli, and Ester Orlandi. "Lower-Neck Sparing Using Proton Therapy in Patients with Uninvolved Neck Nasopharyngeal Carcinoma: Is It Safe?" Journal of Clinical Medicine 11, no. 12 (June 9, 2022): 3297. http://dx.doi.org/10.3390/jcm11123297.
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Undifferentiated carcinoma of the nasopharynx (NPC) is a rare disease, which usually occurs in the Asian population. Due to its anatomic location, it is characterised by rich lymph node drainage and has a high incidence of cervical node metastasis. However, cervical nodal metastasis commonly involves retropharyngeal nodes and level II nodes, followed by level III nodes. In recent years, innovations in terms of systemic treatments and radiotherapy techniques have improved oncological outcome and treatment-related toxicities. Therefore, there is a growing interest in de-intensification strategies of reducing volumes and treatment-related side effects, especially in patients with NPC with N0–N1-stage disease. Proton therapy could represent a valid alternative to Intensity Modulated Radiotherapy (IMRT) in the management of NPC in this setting. With this Commentary, we aim to explore the feasibility of Intensity Modulated Proton Therapy (IMPT) in upper-neck irradiation of NPC N1-stage disease. We selected an NPC patient with N1 disease and compared the original IMRT plan with the IMPT plan in terms of dosimetric parameters. IMPT offers a minimal dosimetric advantage over IMRT in the bilateral lower-neck sparing. Clinical trials are needed to evaluate the significance of these proposed suggestions and their applicability in non-endemic areas.
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Taparra, Kekoa, Scott C. Lester, W. Scott Harmsen, Molly Petersen, Ryan K. Funk, Miran J. Blanchard, Phillip Young, et al. "Reducing Heart Dose with Protons and Cardiac Substructure Sparing for Mediastinal Lymphoma Treatment." International Journal of Particle Therapy 7, no. 1 (June 1, 2020): 1–12. http://dx.doi.org/10.14338/ijpt-20-00010.1.
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Abstract Purpose Electrocardiogram-gated computed tomography with coronary angiography can be used for cardiac substructure sparing (CSS) optimization, which identifies and improves avoidance of cardiac substructures when treating with intensity modulated radiotherapy (IMRT). We investigated whether intensity modulated proton therapy (IMPT) would further reduce dose to cardiac substructures for patients with mediastinal lymphoma. Patients and Methods Twenty-one patients with mediastinal lymphoma were enrolled and underwent electrocardiogram-gated computed tomography angiography during or shortly after simulation for radiotherapy planning. Thirteen patients with delineated cardiac substructures underwent comparative planning with both IMPT and IMRT. Plans were normalized for equivalent (95%) target volume coverage for treatment comparison. Results Thirteen patients met criteria for this study. The median size of the mediastinal lymphadenopathy was 7.9 cm at the greatest diameter. Compared with IMRT-CSS, IMPT-CSS significantly reduced mean dose to all cardiac substructures, including 3 coronary arteries and 4 cardiac valves. Use of IMPT significantly reduced average whole-heart dose from 9.6 to 4.9 Gy (P < .0001), and average mean lung dose was 9.7 vs 5.8 Gy (P < .0001). Prospectively defined clinically meaningful improvement was observed in at least 1 coronary artery in 9 patients (69%), at least 1 cardiac valve in 10 patients (77%), and whole heart in all 13 patients. Conclusions For patients with mediastinal lymphoma, IMPT-CSS treatment planning significantly reduced radiation dose to cardiac substructures. The significant improvements outlined in this study for proton therapy suggest possible clinical improvement in alignment with previous analyses of CSS optimization.
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Agazaryan, Nzhde, Wolfgang Ullrich, Steve P. Lee, and Timothy D. Solberg. "A methodology for verification of radiotherapy dose calculation." Journal of Neurosurgery 101, Supplement3 (November 2004): 356–61. http://dx.doi.org/10.3171/sup.2004.101.supplement3.0356.
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Object. A methodology for dosimetric verification of radiation therapy plans was developed and implemented. Dosimetric accuracy of clinically active intensity-modulated radiotherapy (IMRT) and intensity-modulated radiosurgery (IMRS) programs was assessed using this methodology. Methods. The methodology included several dosimetric tasks that were performed to assess the dosimetric accuracy of a treatment plan. Absolute dosimetry of the composite plan was performed using an ionization chamber. Film dosimetry was performed for each individual field and for the multifield composite plan. Calculated dose distributions and film measurements were compared using software developed for the specific tasks. Two-dimensional maps of gamma index, dose difference, and distance-to-agreement were calculated and displayed. To date, good agreement between measurements and calculations has been observed in 160 clinical IMRT and IMRS plans. The largest observed absolute dose disagreement was −4.79%. The mean absolute dose difference was 0.26%, with a standard deviation of 1.75%. The authors specify a 3% dose difference and 3-mm distance as the scaling acceptability criteria for the gamma index calculations of the film measurement analysis. The planning and delivery system in clinical use has proven consistently to satisfy these criteria. Conclusions. The dosimetric verification methods and the software tools developed were both quantitative and clinically practical. The measurements and the analysis demonstrated that the IMRT and IMRS planning and delivery system in use was sufficiently accurate for highly conformal treatments.
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Oelfke, U., and T. Bortfeld. "Optimization of Physical Dose Distributions with Hadron Beams: Comparing Photon IMRT with IMPT." Technology in Cancer Research & Treatment 2, no. 5 (October 2003): 401–12. http://dx.doi.org/10.1177/153303460300200505.
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Intensity modulated radiotherapy with high enengy photons (IMRT) and with charged particles (IMPT) refer to the most advanced development in conformal radiation therapy. Their general aim is to increase local tumor control rates while keeping the radiation induced complications below desired thresholds. IMRT is currently widely introduced in clinical practice. However, the more complicated IMPT is still under development. Especially, spot-scanning techniques integrated in rotating gantries that can deliver proton or light ion-beams to a radiation target from any direction will be available in the near future. We describe the basic concepts of intensity modulated particle therapy (IMPT). Starting from the potential advantages of hadron therapy inverse treatment planning strategies are discussed for various dose delivery techniques of IMPT. Of special interest are the techniques of distal edge tracking (DET) and 3D-scanning. After the introduction of these concepts a study of comparative inverse treatment planning is presented. The study aims to identify the potential advantages of achievable physical dose distributions with proton and carbon beams, if different dose delivery techniques are employed. Moreover, a comparison to standard photon IMRT is performed. The results of the study are summarized as: i) IMRT with photon beams is a strong competitor to intensity modulated radiotherapy with charged particles. The most obvious benefit observed for charged particles is the reduction of medium and low doses in organs at risk. ii) The 3D-scanning technique could not improve the dosimetric results achieved with DET, although 10–15 times more beam spots were employed for 3D-scanning than for DET. However, concerns may arise about the application of DET, if positioning errors of the patient or organ movements have to be accounted for. iii) Replacing protons with carbon ions leads to further improvements of the physical dose distributions. However, the additional degree of improvement due to carbon ions is modest. The main clinical potential of heavy ion beams is probably related to their radiobiological properties.
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Dell’Oro, Mikaela, Michala Short, Puthenparampil Wilson, Chia-Ho Hua, Melissa Gargone, Thomas E. Merchant, and Eva Bezak. "Influence of Target Location, Size, and Patient Age on Normal Tissue Sparing- Proton and Photon Therapy in Paediatric Brain Tumour Patient-Specific Approach." Cancers 12, no. 9 (September 10, 2020): 2578. http://dx.doi.org/10.3390/cancers12092578.
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Background: Proton radiotherapy produces superior dose distributions compared to photon radiotherapy, reducing side effects. Differences between the two modalities are not fully quantified in paediatric patients for various intracranial tumour sites or age. Understanding these differences may help clinicians estimate the benefit and improve referral across available centres. Our aim was to compare intensity-modulated proton therapy (IMPT) and intensity-modulated photon radiotherapy (IMRT) radiation doses for select paediatric intracranial tumours. Methods: IMPT and IMRT dose distributions for gender-matched paediatric cranial CT-datasets (ages 5, 9 and 13 years) were retrospectively calculated to simulate irradiation of supratentorial (ependymoma) and infratentorial (medulloblastoma) target volumes diameters (1–3 cm) and position (central and 1–2 cm shifts). Results: Clinical dosimetric objectives were achieved for all 216 treatment plans. Whilst infratentorial IMPT plans achieved greater maximum dose sparing to optic structures (4.8–12.6 Gy optic chiasm), brainstem sparing was limited (~0.5 Gy). Mean dose difference for optic chiasm was associated with medulloblastoma target position (p < 0.0197). Supratentorial IMPT plans demonstrated greater dose reduction for the youngest patients (pituitary gland p < 0.001). Conclusions: Normal tissue sparing was achieved regardless of patient age for infratentorial tumours. However, for supratentorial tumours, there was a dosimetric advantage of IMPT across 9 vs. 13-year-old patients.
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Allen, Aaron M., Luciant Wolfsberger, Roy B. Tishler, and Laurence E. Court. "Options for Combining Altered Fractionation with IMRT." Technology in Cancer Research & Treatment 7, no. 6 (December 2008): 457–61. http://dx.doi.org/10.1177/153303460800700607.
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We set out to investigate IMRT-based concomitant boost. Eight patients with stage III/IV squamous cell carcinoma of the head and neck treated with once daily with chemoradiotherapy at the Dana-Farber/Brigham and Women's Hospital had their treatment plans reviewed with IRB approval. Each case was replanned for treatment with a a concomitant boost regimen. Plans delivered 1.9 Gy in 30 fractions to 57 Gy with a boost of 1.5 Gy in 10 fractions for a total dose of 72 Gy. The boost was planned with both IMRT and 3-D conformal, to compare the two techniques. For each patient, both plans (IMRT-IMRT and IMRT-3DCRT) were evaluated for target and avoidance coverage, monitor units and integral dose. Finally, we evaluated the plans for time to completion. The IMRT-IMRT and IMRT-3-DCRT techniques were equivalent for target coverage. 100% coverage of the GTV and PTV was achieved with 97% of the prescription dose. Hot spots were seen 104% to 108% with IMRT-IMRT plan and from 102–111% with the IMRT-3DCRT plans. The IMRT-IMRT boost had double the monitor units as the 3-DCRT boosts. When the total monitor units from both the initial and boost portions of the plans were e combined there was not a significant differnce. There was a slight increase in integral dose with the IMRT-IMRT plans of mean 3.8%. Planning time was increased for the 3-DCRT boost as opposed to the IMRT boost (mean 3.5 hours vs. 1.5 hours). More time was needed for quality assurance of the IMRT-IMRT plans (3.0 hours vs. 1.5 hours for IMRT-3-DCRT). We found that both IMRT-based concomitant-boost strategies are achievable and produce good dosimetric results.
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Bicakci, Beyhan C., Fatih Demircioglu, Sevecen S. N. Can, and Ozlem Demircioglu. "Optimal plan target in cases with locally advanced nasopharyngeal cancer: Comparison of VMAT, IMRT, hybrid, and tomotherapy results." Journal of Cancer Research and Therapeutics 19, Suppl 2 (2023): S731—S736. http://dx.doi.org/10.4103/jcrt.jcrt_298_22.
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ABSTRACTS Purpose: In locally advanced nasopharyngeal cancer (NC), the spread of the disease, proximity to critical structures, and high dose requirement for tumor control may complicate the treatment plan. In this study, VMAT/IMRT/hybrid/tomotherapy plans were made to reach the safest and most effective dose distribution for each of the patients and the results were compared. Methods: Double volumetric-modulated arc therapy (VMAT) and 7- and 9-field intensity-modulated radiation therapy (IMRT) plans were made to 21 locally advanced NCs with Varian Trilogy System. It was observed that appropriate dose distributions could not be achieved with IMRT or VMAT, and hybrid IMRT–VMAT plans were made. All cases were also planned with Tomotherapy Precision System, and the data of four different techniques were compared retrospectively. Results: For normal tissue tolerances in 73 structures could not be obtained with VMAT and 38 structures with IMRT whereas the desired tolerance was provided with the hybrid plan. Hybrid plans were made with an average of 14 VMATs and 20 IMRTs. The maximum brainstem and spinal cord doses were found significantly lower in hybrid and tomotherapy techniques. Homogeneity index (HI) and conformity index (CI) values were the best in hybrid plans. No statistically significant difference between the hybrid plan and tomotherapy in terms of normal tissue tolerance doses and HI whereas a significant difference was found in the hybrid plan for CI. Conclusion: It was observed that the most ideal plans for the locally advanced NC could be obtained with tomotherapy and hybrid plan techniques that the better protection in critical structures and desired dose distribution at target volumes.
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Ahmad, Irfan, Kundan Singh Chufal, Chandi Prasad Bhatt, Alexis Andrew Miller, Ram Bajpai, Akanksha Chhabra, Rahul Lal Chowdhary, Anjali Kakria Pahuja, and Munish Gairola. "Plan quality assessment of modern radiotherapy delivery techniques in left-sided breast cancer: an analysis stratified by target delineation guidelines." BJR|Open 2, no. 1 (November 2020): 20200007. http://dx.doi.org/10.1259/bjro.20200007.
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Objective: This study compares planning techniques stratified by consensus delineation guidelines in patients undergoing whole-breast radiotherapy based on an objective plan quality assessment scale. Methods: 10 patients with left-sided breast cancer were randomly selected, and target delineation for intact breast was performed using Tangent (RTOG 0413), ESTRO, and RTOG guidelines. Consensus Plan Quality Metric (PQM) scoring was defined and communicated to the physicist before commencing treatment planning. Field-in-field IMRT (FiF), inverse IMRT (IMRT) and volumetric modulated arc therapy (VMAT) plans were created for each delineation. Statistical analyses utilised a two-way repeated measures analysis of variance, after applying a Bonferroni correction. Results: Total PQM score of plans for Tangent and ESTRO were comparable for FiF and IMRT techniques (FiF vs IMRT for Tangent, p = 0.637; FiF vs IMRT for ESTRO, p = 0.304), and were also significantly higher compared to VMAT. Total PQM score of plans for RTOG revealed that IMRT planning achieved a significantly higher score compared to both FiF and VMAT (IMRT vs FiF, p < 0.001; IMRT vs VMAT, p < 0.001). Conclusions: Total PQM scores were equivalent for FiF and IMRT for both Tangent and ESTRO delineations, whereas IMRT was best suited for RTOG delineation. Advances in knowledge: FiF and IMRT planning techniques are best suited for ESTRO or Tangent delineations. IMRT also yields better results with RTOG delineation.
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Zhao, Nan, Ruijie Yang, Yuliang Jiang, Suqing Tian, Fuxin Guo, and Junjie Wang. "A Hybrid IMRT/VMAT Technique for the Treatment of Nasopharyngeal Cancer." BioMed Research International 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/940102.
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Hybrid IMRT/VMAT technique which combined intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) was developed for the treatment of nasopharyngeal cancer (NPC). Two-full-arc VMAT (2ARC-VMAT), 9-field IMRT (9F-IMRT), and Hybrid IMRT/VMAT plans for NPC were compared in terms of the dosimetric quality, sparing of organs at risk (OARs), and delivery efficiency. The Hybrid IMRT/VMAT technique can improve the target dose homogeneity and conformity compared with 9F-IMRT and 2ARC-VMAT. It can reduce the dose delivered to the TMJ, mandible, temporal lobe, and unspecified tissue with fewer MUs compared with 9F-IMRT and dose delivered to parotids, brainstem, and spinal cord compared with 2ARC-VMAT technique. The mean delivery time of Hybrid plans was shorter than that of 9F-IMRT plans (408 s versus 812 s;P=0.00) and longer than that of 2ARC-VMAT plans (408 s versus 179 s;P=0.00). Hybrid IMRT/VMAT technique could be a viable radiotherapy technique with better plan quality.
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Sakthivel, Vasanthan, Ganesh Kadirampatti Mani, Sunil Mani, and Raghavendiran Boopathy. "Radiation-induced second cancer risk from stereotactic ablative radiotherapy (SABR) for lung cancer: a review of planning studies." Journal of Radiotherapy in Practice 17, no. 2 (October 11, 2017): 194–204. http://dx.doi.org/10.1017/s1460396917000528.
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AbstractPurposeThe aim of the current study was to (i) to calculate organ equivalent dose (OED) and (ii) to estimate excess absolute risks (EARs), lifetime attributable risks (LARs) and relative risks (RRs) from stereotactic ablative radiotherapy (SABR) for lung cancer to in-field, close to field, and out of field structures.MethodsA total of five patients with T1, T2 (≤4 cm), N0, M0 medically inoperable non-small cell lung cancer were selected for treatment planning. Patient selection criteria were based on RTOG 0236. Five treatment deliveries were investigated: (i) three-dimensional conformal radiotherapy (3DCRT), (ii) intensity-modulated radiotherapy (IMRT), (iii) intensity-modulated radiotherapy with flattening filter free beam (IMRTF), (iv) volumetric modulated arc therapy (VMAT) and (v) volumetric modulated arc therapy with flattening filter free arcs (VMATF). Delineated normal structures included chest wall, left and right lung, trachea, small and large airways, spinal cord, oesophagus and involved ribs. All plans were prescribed to 60 Gy in five fractions to primary planning target volume (PTV) volume so that ≥98% of the PTV received ≥98% of the prescription dose and internal tumour volume received 100% of the prescription dose. The OED for all delineated normal structures was calculated using differential dose volume histograms. Using risk models, the age-dependent LAR’s and RR were calculated. Additionally, the secondary cancer risk for organs inside primary radiation was analysed using sarcoma and carcinoma risk models.ResultsFor all patients, the mean V20 volumes from the SABR plans were 4·1% (3DRT), 11·8% (IMRT), and 12·7% (VMAT), respectively. The EAR (combining all organs EAR) for all the organs studied, ranged from 8·5 to 10·6/10,000 persons/year for VMATF and 3DCRT, respectively. The EAR (combining all organs EAR) for all the organs studied, ranged from 8·5 to 10·6/10,000 persons/year for VMATF and 3DCRT, respectively. The absolute EAR difference between IMRT and IMRTF was low ranging from 0·2 to 0·4/10,000 persons-year, whereas delivery difference (IMRT and VMAT) had a significant impact on EAR with absolute difference ranging from 0·5 to 1·0/10,000 persons-year for IMRT and VMAT and 1·1–1·5/10,000 persons-year for IMRTF, VMATF, respectively. The LAR data showed a strong dependence on age at exposure and the LAR decreased as a function of age at exposure. The absolute attributable risk of bone sarcoma was lower with the VMAT plan and was significantly higher with the 3DCRT plan.ConclusionFrom a clinical perspective, it should be concluded that all five solutions investigated in the study can offer high quality of patient treatments and only estimates of radiation-induced malignancies can truly differentiate among them. The results suggested it would be reasonable to use the cumulative LAR difference when needed to select between treatment techniques. In conclusion, the LAR of radiation-induced secondary cancer was significantly lower when using VMATF than when using IMRT for SABR lung patients. VMATF would be the right choice for the treatment of SABR lung patients in terms of LAR. However, more work is required for the specific estimation and long-term validation and updating of the models behind LAR estimation.
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Chen, Shang-Wen, Ji-An Liang, Lian-Shung Yeh, Wei-Chun Chang, Wu-Chou Lin, and Chun-Ru Chien. "Does initial 45Gy of pelvic intensity-modulated radiotherapy reduce late complications in patients with locally advanced cervical cancer? A cohort control study using definitive chemoradiotherapy with high-dose rate brachytherapy." Radiology and Oncology 47, no. 2 (June 1, 2013): 176–84. http://dx.doi.org/10.2478/raon-2013-0011.
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Background. Comparing initial 45 Gy of pelvic intensity-modulated radiation therapy (IMRT) and non-IMRT in terms of the late toxicities associated with advanced cervical cancer that has also been treated with definitive concurrent chemoradiotherapy and high-dose rate intracavitary brachytherapy (HDRICB). Patients and methods. This retrospective study included 320 stage IB2-IIIB cervical cancer patients treated with CCRT (83 IMRT and 237 non-IMRT). The two groups had similar stage and HDRICB ratings. Following 45 Gy to the pelvis, HDRICB of 24 Gy in four courses was prescribed. Late toxicities, including rectal complications (RC), bladder complications (BC) and non-rectal intestinal injury (NRRII), were scored by the Common Terminology Criteria for Adverse Events. A logistic regression was used to estimate the odds ratio (OR) of the complications. Results. With a median follow-up duration of 33 and 77 months for IMRT and non-IMRT, 33 patients had Grade 2 or higher late RC (7.2% IMRT, 11.4% non-IMRT), whereas that for BC was 40 (9.6% IMRT, 13.5% non-IMRT) and for NRRII was 48 (12.0% IMRT, 16.0% non-IMRT). The cumulative rate for total grade 3 or higher gastrointestinal or genitourinary toxicities was 8.4% and 11.8% (p = 0.33). IMRT did not reduce the OR for all endpoints; however, the ORs for rectum and bladder reference doses to Point A were associated with RC and BC. Conclusions. Locally advanced cervical cancer patients treated with initial 45Gy of pelvic IMRT and HDRICB have similar treatment-related late toxicities as those treated with non-IMRT. Optimization of the brachytherapy scheme is essential to minimize late toxicities.
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Nutting, Christopher, Keith Rooney, Bernadette Foran, Laura Pettit, Matthew Beasley, Laura Finneran, Justin Roe, et al. "Results of a randomized phase III study of dysphagia-optimized intensity modulated radiotherapy (Do-IMRT) versus standard IMRT (S-IMRT) in head and neck cancer." Journal of Clinical Oncology 38, no. 15_suppl (May 20, 2020): 6508. http://dx.doi.org/10.1200/jco.2020.38.15_suppl.6508.
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6508 Background: Most newly diagnosed oro- & hypopharngeal cancers (OPC, HPC) are treated with (chemo)RT with curative intent but at the consequence of adverse effects on quality of life. CRUK/14/014 investigated if using Do-IMRT to reduce RT dose to the dysphagia/aspiration related structures (DARS) improved swallowing function compared to S-IMRT. Methods: Patients with T1-4, N0-3, M0 OPC/HPC were randomised 1:1 to S-IMRT (65 Gray (Gy)/30 fractions (f) to primary & nodal tumour; 54Gy/30f to remaining pharyngeal subsite & nodal areas at risk of microscopic disease) or Do-IMRT. The volume of the superior & middle pharyngeal constrictor muscle (PCM) (OPC) or inferior PCM (HPC) lying outside the high-dose target volume was set a mandatory mean dose constraint in Do-IMRT. Treatment allocation was by minimisation balanced by centre, use of induction/concomitant chemotherapy, tumour site & AJCC stage. Primary endpoint was mean MD Anderson Dysphagia Inventory (MDADI) composite score 12 months after RT with 102 patients needed to detect a 10 point improvement (assuming S-IMRT score of 72, standard deviation (SD) 13.8; 90% power, 2-sided 5% alpha). Patients were blind to treatment allocation. Secondary endpoints included local control. Results: 112 patients (56 S-IMRT, 56 Do-IMRT) were randomised from 22 UK centres from 06/2016 to 04/2018. Mean age was 57 years; 80% were male; 97% had OPC; 90% had AJCC stage 3&4 disease; 86% had concomitant chemotherapy only, 4% induction & concomitant and 10% no chemotherapy. 111/112 had RT doses as prescribed (1 patient died before RT). Median of the mean inferior PCM dose was S-IMRT 49.8Gy (IQR 47.1-52.4) vs. Do-IMRT 28.4Gy (21.3–37.4), p < 0.0001; superior & middle PCM dose was S-IMRT 57.2Gy (56.3–58.3) vs. Do-IMRT 49.7Gy (49.4–49.9), p < 0.0001. Do-IMRT had significantly higher MDADI scores: S-IMRT 70.3 (SD 17.3) vs. Do-IMRT 77.7 (16.1), p = 0.016. 3 local recurrences (1 S-IMRT, 2 Do-IMRT) have been reported. Conclusions: Do-IMRT reduced RT dose to the DARS and improved patient reported swallowing function compared with S-IMRT. This is the first randomised study to demonstrate functional benefit of swallow-sparing IMRT in OPC. Clinical trial information: 25458988 .
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Eziokwu, Akaolisa Samuel, Shlomo A. Koyfman, Chandana A. Reddy, Brian Matia, Neil McIver Woody, Nikhil Purushottam Joshi, Brian B. Burkey, et al. "Incidence of severe late toxicities of head and neck squamous cell cancer (HNSCC) treatment in the era of intensity modulated radiotherapy (IMRT)." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e17570-e17570. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e17570.
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e17570 Background: IMRT for HNSCC limits exposure to critical nearby structures thereby reducing toxicities. Real world data on toxicities after long term follow-up post IMRT for HNSCC are lacking. This study assessed the incidence of late toxicities in patients with HNSCC within 5 years post-treatment with definitive IMRT (d-IMRT). Methods: This is a retrospective, IRB approved, single-institution review of patients (pts) with stage I-IVB HNSCC treated with d-IMRT +/- chemotherapy between 2009 and 2013. The primary outcomes were incidence of severe late toxicities (dysphagia requiring esophageal stricture dilation, physician-reported grade 2 or worse neck fibrosis and xerostomia) occurring 3 months or more after completion of IMRT; feeding tube (FT) dependence within 1st year of IMRT completion, and FT dependence beyond 1st year post IMRT. Toxicities were deemed acute if they occurred during IMRT and up to 90 days post IMRT. Results: 274 pts, median age 59 years (38 – 82.9), were identified. 67.6% were HPV positive, 10.5% HPV negative and HPV status was unknown in 21.9%. Site of disease was oropharynx in 70%, larynx in 25% and hypopharynx in 4%. 206 pts (75.2%) received d-IMRT alone, 37 (13.5%) had definitive concurrent chemoradiation – mostly with cisplatin (58%), and 31 (11.3%) received adjuvant IMRT. Of the 243 pts treated with d-IMRT +/- chemotherapy, 80 (32.9%) required FT during RT due to grade 2 or worse acute dysphagia. Excluding 11 pts with disease recurrence or new HNSCC diagnosis, FT dependence at any time from 3 months to one year post IMRT occurred in 22 of 232 pts (9.48%), while FT dependence beyond 1st year post IMRT occurred in 8 pts (3.4%). 11 pts (4.7%) required stricture dilation for late dysphagia. Late grade 2 or worse fibrosis and xerostomia occurred in 7 (3.0%) and 89 (38.4%) pts, respectively. Conclusions: Our study suggests that except for xerostomia, severe late toxicities after definitive IMRT for HNSCC is likely uncommon. Prospective studies with late IMRT toxicities and their impact on quality of life (QoL) as endpoints are warranted.
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Rikitake, Ryoko, Yoichiro Tsukada, Mizuo Ando, Masafumi Yoshida, Momoko Iwamoto, Tatsuya Yamasoba, and Takahiro Higashi. "Use of intensity-modulated radiation therapy for nasopharyngeal cancer in Japan: analysis using a national database." Japanese Journal of Clinical Oncology 49, no. 7 (April 27, 2019): 639–45. http://dx.doi.org/10.1093/jjco/hyz042.
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Abstract Background Intensity-modulated radiation therapy (IMRT) yields better outcomes and fewer toxicities for radiation therapy (RT) of head and neck cancers (HNCs), including nasopharyngeal cancer (NPC). IMRT is the standard RT treatment and has been widely adopted in Western countries to treat HNCs. However, its uptake in clinical practice among NPC patients has never been studied. Methods We investigated the use of IMRT for NPC using data from a nationwide cancer registry to describe the use of IMRT among NPC patients in Japan. We analyzed the data of patients with HNC, including NPC, who underwent IMRT between 2012 and 2014, as recorded in the hospital-based cancer registries linked with insurance claims. We calculated the proportion of patients with NPC who underwent IMRT at each hospital. To evaluate the use of IMRT for NPC, the IMRT use for NPC was compared with the proportion of patients with prostate cancer who underwent IMRT. Results Among 508 patients with NPC who underwent RT at one of 87 hospitals, 348 (69%) underwent IMRT. This proportion gradually increased between 2012 and 2014 (62%, 64% and 77%). Meanwhile, 4790 patients with prostate cancer (90%) underwent IMRT. Although some hospitals where IMRT was performed treated many patients with NPC, the proportion of patients with NPC who were treated with IMRT was low. Conclusions IMRT has not been widely adopted in Japan for treating NPC. Barriers for adopting its use should be identified to close the gap between the standard and actual medical practice in Japan.
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Pinnaduwage, Dilini S., Martina Descovich, Michael W. Lometti, Badri Varad, Mack Roach, and Alexander R. Gottschalk. "An Evaluation of Robotic and Conventional IMRT for Prostate Cancer: Potential for Dose Escalation." Technology in Cancer Research & Treatment 16, no. 3 (March 31, 2016): 267–75. http://dx.doi.org/10.1177/1533034616639729.
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This study compares conventional and robotic intensity modulated radiation therapy (IMRT) plans for prostate boost treatments and provides clinical insight into the strengths and weaknesses of each. The potential for dose escalation with robotic IMRT is further investigated using the “critical volume tolerance” method proposed by Roach et al. Three clinically acceptable treatment plans were generated for 10 prostate boost patients: (1) a robotic IMRT plan using fixed cones, (2) a robotic IMRT plan using the Iris variable aperture collimator, and (3) a conventional linac based IMRT (c-IMRT) plan. Target coverage, critical structure doses, homogeneity, conformity, dose fall-off, and treatment time, were compared across plans. The average bladder and rectum V75 was 17.1%, 20.0%, and 21.4%, and 8.5%, 11.9%, and 14.1% for the Iris, fixed, and c-IMRT plans, respectively. On average the conformity index (nCI) was 1.20, 1.30, and 1.46 for the Iris, fixed, and c-IMRT plans. Differences between the Iris and the c-IMRT plans were statistically significant for the bladder V75 (P= .016), rectum V75 (P= .0013), and average nCI (P =.002). Dose to normal tissue in terms of R50 was 4.30, 5.87, and 8.37 for the Iris, fixed and c-IMRT plans, respectively, with statistically significant differences between the Iris and c-IMRT (P = .0013) and the fixed and c-IMRT (P = .001) plans. In general, the robotic IMRT plans generated using the Iris were significantly better compared to c-IMRT plans, and showed average dose gains of up to 34% for a critical rectal volume of 5%.
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Daly, M. E., Y. Lieskovsky, T. Pawlicki, J. Yau, H. Pinto, M. Kaplan, A. Koong, D. R. Goffinet, L. Xing, and Q. Le. "Evaluation of patterns of failure and subjective salivary function in patients treated with intensity modulated radiotherapy for head and neck squamous cell carcinomas." Journal of Clinical Oncology 24, no. 18_suppl (June 20, 2006): 5536. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.5536.
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5536 Background: Conventional RT (CRT) for head and neck squamous cell carcinoma (HNSCC) is associated with severe late side effects which can worsen quality of life of surviving patients. Intensity-modulated radiotherapy (IMRT) allows the delivery of tumoricidal doses to the target volume while maintaining tolerable doses to critical organs. Several previous studies have demonstrated promising results for tumor control and disease free survival for HNSCC treated with IMRT. In this study, we correlated patterns of failure with target volume delineations in HNSCC treated with IMRT at our instittuion and evaluated subjective xerostomia outcomes after IMRT as compared to CRT. Material and Methods: Between 1/00 and 4/05, 69 patients with newly diagnosed non-metastatic HNSCC underwent curative parotid sparing IMRT at Stanford University. Sites included were oropharynx (39), oral cavity (8), larynx (8), hypopharynx (8) and unknown primary (6). Forty-six patients received definitive IMRT (66 Gy, 2.2 Gy/fraction), and 23 patients received post-operative IMRT (60.2 Gy, 2.15 Gy/fraction). Fifty-one patients also received concomitant chemotherapy. Post-treatment salivary gland function was evaluated by a validated xerostomia questionnaire (XQ) in 29 IMRT and 75 matched non-IMRT patients > 6 months after completing RT. Results: At a median follow-up of 17 months for living patients (range 6.5–60), 7 locoregional failures were observed, 5 in the gross target volume (GTV), 1 in the clinical target volume (CTV), and 1 at the junction of the IMRT and supraclavicular fields. The 2-year Kaplan Meier estimates of locoregional control and overall survival were 92% and 80% for definitive IMRT and 85% and 85% for post-op IMRT patients, respectively. The mean total XQ score was significantly better for IMRT than for non-IMRT patients (p = 0.006). Conclusions: The predominant pattern of failure in IMRT treated patients is in the GTV. Parotid sparing with IMRT resulted in decreased subjective xerostomia and may improve quality of life in irradiated HNSCC patients. No significant financial relationships to disclose.
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Ibrahim, Mohamed S., Ehab M. Attalla, Mostafa El Naggar, and Wael M. Elshemey. "Dosimetric comparison between three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in the treatment of different stages of nasopharyngeal carcinoma." Journal of Radiotherapy in Practice 18, no. 1 (September 10, 2018): 46–51. http://dx.doi.org/10.1017/s1460396918000377.
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AbstractBackgroundThis work aims to compare the dosimetric performance of three-dimensional conformal radiotherapy (3D-CRT), a relatively available technique in developing countries, to intensity-modulated radiotherapy (IMRT) in the treatment of different stages of nasopharyngeal carcinoma (NPC).Materials and MethodsAccording to the diagnostic stages, 40 NPC patients were divided into two equal groups. Three planning techniques such as 3D-CRT, seven-field IMRT (7F-IMRT) and nine-field IMRT (9F-IMRT) were compared. Dose prescriptions of 70 and 66 Gy were delivered in 35 fractions to gross planning target volume (PTV1) and bilateral retropharyngeal carcinoma (PTV2), respectively.ResultsStage I dose data for almost all of the three investigated planning techniques obey the international recommendations. The dose delivered to PTV1 and PTV2 for 3D-CRT and 7F-IMRT are statistically similar, whereas 9F-IMRT is significantly better than 3D-CRT. For organs at risk (OARs), the delivered dose is significantly better for 9F-IMRT compared with the other two techniques, whereas 7F-IMRT is significantly better than 3D-CRT.Conclusions3D-CRT is an acceptable alternative treatment technique for stage I NPC patients in developing countries suffering from the lack of advanced radiotherapy treatment techniques. 3D-CRT and 7F-IMRT have comparable performance in PTVs, while 9F-IMRT is superior in PTVs and OARs.
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Azelie, Caroline, Mélanie Gauthier, Céline Mirjolet-Didelot, Luc Cormier, Etienne Martin, Karine Peignaux-Casasnovas, Gilles Truc, Philippe Maingon, and Gilles Crehange. "Exclusive image-guided IMRT versus radical prostatectomy followed by postoperative IMRT for localized prostate cancer: A matched-pair analysis based on risk groups." Journal of Clinical Oncology 30, no. 5_suppl (February 10, 2012): 135. http://dx.doi.org/10.1200/jco.2012.30.5_suppl.135.
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135 Background: To investigate whether patients treated for a localized prostate cancer require prior radical prostatectomy followed by postoperative radiotherapy or exclusive radiotherapy, in the modern era of image-guided IMRT. Methods: One hundred and seventy-eight patients with localized prostate cancer were referred for daily on-line exclusive image-guided IMRT (IG-IMRT), while 69 patients were referred for postoperative IMRT without image guidance after radical prostatectomy (RP+IMRT). The patients were matched in a 1:1 ratio according to their baseline risk group before any treatment. Late toxicity was scored using the CTV v3.0 scale. Biochemical failure was defined as a postoperative PSA ≥ 0.1 ng/mL followed by 1 consecutive rise in PSA for the postoperative group of patients and by the Phoenix definition (nadir+2 ng/mL) for the group of patients treated with exclusive radiotherapy. Results: A total of 98 patients were matched (49:49). Thirty patients had a low-risk (30.6%), 62 patients an intermediate risk (63.3%) and 6 patients a high risk (6.1%). In the RP+IMRT group, the median PSA value before radiotherapy in the RP+IMRT group was 0.28 ng/mL [undetectable-6.99]. The median radiation dose in the IG-IMRT group was 77.4Gy [73.0-79.8 Gy] whereas it was 66.0 Gy [31.4-70.3 Gy] in the RP+IMRT group. The duration of the hormones was similar in both groups (p= 0.438). From the start of any treatment, the median follow-up was 56.6 months (95% CI = [49.6-61.2], range [18.2-115.1]. No patients had late gastrointestinal grade ≥ 2 toxicity in the IG-IMRT group vs. 4% in the RP+IMRT group. Forty-two percent of the patients in both groups had late grade ≥ 2 genitourinary toxicity. The 5-year freedom from biochemical failure rates in the IG-IMRT group and in the RP+IMRT groups were 93.1% [80.0-97.8] and 76.5% [58.3-87.5], respectively (p= 0.031). Conclusions: Patients with localized prostate cancer treated with IG-IMRT had a better oncological outcome than patients treated with RP+IMRT. Further improvements in postoperative IMRT using image guidance and dose escalation need to be evaluated to determine whether it could eventually be superior to IG-IMRT.
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Zhao, Nan, Ruijie Yang, Junjie Wang, Xile Zhang, and Jinna Li. "An IMRT/VMAT Technique for Nonsmall Cell Lung Cancer." BioMed Research International 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/613060.
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The study is to investigate a Hybrid IMRT/VMAT technique which combines intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for the treatment of nonsmall cell lung cancer (NSCLC). Two partial arcs VMAT, 5-field IMRT, and hybrid plans were created for 15 patients with NSCLC. The hybrid plans were combination of 2 partial arcs VMAT and 5-field IMRT. The dose distribution of planning target volume (PTV) and organs at risk (OARs) for hybrid technique was compared with IMRT and VMAT. The monitor units (MUs) and treatment delivery time were also evaluated. Hybrid technique significantly improved the target conformity and homogeneity compared with IMRT and VMAT. The mean delivery time of IMRT, VMAT, and hybrid plans was 280 s, 114 s, and 327 s, respectively. The mean MUs needed for IMRT, VMAT, and hybrid plans were 933, 512, and 737, respectively. Hybrid technique reducedV5,V10,V30, and MLD of normal lung compared with VMAT and spared the OARs better with fewer MUs with the cost of a little higherV5,V10, and mean lung dose (MLD) of normal lung compared with IMRT. Hybrid IMRT/VMAT can be a viable radiotherapy technique with better plan quality.
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Marshall, Deborah C., Zahra Ghiassi-Nejad, Allison Powers, Joy S. Reidenberg, Pamela Argiriadi, Meng Ru, Vishruta Dumane, et al. "A first radiotherapy application of functional bulboclitoris anatomy, a novel female sexual organ-at-risk, and organ-sparing feasibility study." British Journal of Radiology 94, no. 1124 (August 1, 2021): 20201139. http://dx.doi.org/10.1259/bjr.20201139.
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Objective: The bulboclitoris (clitoris and vestibular bulbs) is the primary organ responsible for female sexual arousal and orgasm. Effects of radiotherapy on the bulboclitoris are unknown, as its structure/function has yet to be described in radiotherapy, and it overlaps only partially with the external genitalia structure. Our aim was to: describe bulboclitoris structure, function and delineation; compare volume of and dose delivered to the bulboclitoris vs external genitalia; and, compare bulboclitoris-sparing IMRT (BCS-IMRT) to standard IMRT (S-IMRT) to determine reoptimization feasibility. Methods: Our expert team (anatomist, pelvic radiologist, radiation oncologist) reviewed bulboclitoris anatomy and developed contouring guidance for radiotherapy. 20 female patients with anal cancer treated with chemoradiation were analyzed. Sexual organs at risk (OARs) included the external genitalia and the bulboclitoris. Volumes, dice similarity coefficients (DSCs) and dose received using S-IMRT were compared. Plans were reoptimized using BCS-IMRT. Dose–volume histograms (DVHs) for PTVs and all OARs were compared for BCS-IMRT vs S-IMRT. Results: Bulboclitoris structure, function and delineation are described herein. The bulboclitoris occupies 20cc (IQR:12–24), largely distinct from the external genitalia (DSC <0.05). BCS-IMRT was superior to S-IMRT in reducing the dose to the bulboclitoris, with the greatest reductions in V30 and V40, with no significant changes in dose to other OARs or PTV 1/V95. Conclusion: The bulboclitoris can be contoured on planning imaging, largely distinct from the external genitalia. Compared with S-IMRT, BCS-IMRT dramatically reduced dose to the bulboclitoris in anal cancer planning. BCS-IMRT might safely reduce sexual toxicity compared with standard approaches. Advances in knowledge: The structure and function of the bulboclitoris, the critical primary organ responsible for female sexual arousal and orgasm, has yet to be described in the radiotherapy literature. Structure, function and delineation of the bulboclitoris are detailed, delineation and bulboclitoris-sparing IMRT were feasible, and sparing reduces the dose to the bulboclitoris nearly in half in female patients receiving IMRT for anal cancer, warranting further clinical study.
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Malik, Renuka, Julia L. Oh, John C. Roeske, and Arno J. Mundt. "Survey of Resident Education in Intensity-Modulated Radiation Therapy." Technology in Cancer Research & Treatment 4, no. 3 (June 2005): 303–9. http://dx.doi.org/10.1177/153303460500400310.
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Intensity-modulated radiation therapy (IMRT) has been gaining increasing popularity among practicing physicians in the U.S., but the extent to which radiation oncology residents are taught the principles of this technology and are trained to use IMRT remains unknown. In this paper, we assessed the current level of resident education in IMRT in the United States. Chief residents at all 77 accredited radiation oncology programs were sent a 13-question survey addressing formal didactics and hands-on experience in IMRT. The survey assessed the frequency, subject, and format of IMRT didactics. Questions also addressed the number of IMRT patients and anatomical sites treated, resident involvement in the IMRT process, and the intent of IMRT use. Finally, residents were asked for their opinions on their IMRT education. Sixty-one surveys (79%) were completed. Overall, forty-three respondents (71%) reported receiving formal IMRT didactics, with nearly one-third reporting extensive didactics (≥ 3 lectures/seminars et cetera per year). The most common didactic formats were lectures (95%) and journal clubs (63%), most commonly supervised by physicists (98%). Involvement by physicians and radiobiologists were reported by 63% and 7% of respondents, respectively. Overall, 87% of respondents had hands-on IMRT training, with nearly one-half having treated >25 patients. The most common sites treated were head and neck (94%) and prostate (81%). Involvement in all aspects of the IMRT process was common, particularly target and tissue delineation (98%) and plan evaluation (93%). Most respondents (79%) with hands-on experience reported receiving formal didactics. However, nearly one-third received no or only minimal formal didactics. The percentage of respondents desiring increased IMRT didactics and hands-on experience were 70% and 47%, respectively. Our results suggest that the great majority of radiation oncology residents in the United States are currently exposed to didactics and hands-on training in IMRT. Areas of potential improvement include increased involvement of physicians and radiobiologists in formal IMRT didactics.
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Erraoudi, M., M. A. Youssoufi, F. Bentayeb, and M. R. Malisan. "A planning study to optimise a simultaneously integrated boost treatment of larynx cancer with seven intensity-modulated radiation therapy (IMRT) beams." Journal of Radiotherapy in Practice 17, no. 4 (July 30, 2018): 447–54. http://dx.doi.org/10.1017/s1460396918000201.
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AbstractBackgroundIntensity-modulated radiation therapy (IMRT) is one of the most reported techniques for head and neck cancer treatment, as it allows a good coverage of the planning target volume (PTV) while sparing the surrounding organs at risk (OAR) better than conventional conformal radiotherapy. The objective of this work is to optimise an IMRT technique for the simultaneously integrated boost (SIB) treatment of larynx cancer delivering a total dose of 69·96 Gy to the boost volume and 54·45 Gy to the elective volume in 33 fractions.MethodsThree IMRT techniques, each using seven equally spaced beams, were planned for a sample of 10 patients. The first two techniques (IMRT-0 and IMRT-26) differ only for the starting angle of the seven beams, whereas the third (IMRT-CT) combines both these techniques by delivering IMRT-0 in the first half of treatment, and IMRT-26 in the second half, thus taking advantage of using 14 beams in total while using seven at a time only. The planning results were compared according to the dose coverage, homogeneity and conformity of the two PTVs, as well as to the dose to OARs, that is, spinal cord, parotids, mandible, brainstem and healthy tissue (defined as the body volume minus the sum of PTVs).ResultsBasically the PTV coverage resulted acceptable and comparable with all the three techniques. Concerning OARs, statistically better results are obtained in IMRT-CT when compared with IMRT-26 and IMRT-0.ConclusionThe IMRT-CT technique, combining two different seven-beam setups, delivered in two treatment phases, improves dose distribution without increasing delivery time.
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Ding, Shouliang, Yongbao Li, Hongdong Liu, Rui Li, Bin Wang, Jun Zhang, Yan Chen, and Xiaoyan Huang. "Comparison of Intensity Modulated Radiotherapy Treatment Plans Between 1.5T MR-Linac and Conventional Linac." Technology in Cancer Research & Treatment 20 (January 1, 2021): 153303382098587. http://dx.doi.org/10.1177/1533033820985871.
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In this study, we assess the dosimetric qualities and usability of planning for 1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various clinical sites in comparison with IMRT plans using a conventional linac. In total of 30 patients with disease sites in the brain, esophagus, lung, rectum and vertebra were re-planned retrospectively for simulated MRL-IMRT using the Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01). Currently, the step-and-shoot (ss) is the only delivery technique for IMRT available on Unity. All patients were treated on an Elekta Versa HDTM with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was recalculated with the same machine and TPS but only changing the technique to step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformality Index, were compared with the clinical plans. The planning usability was measured by the optimization time and the number of Monitor Units (MUs). Comparing MRL-IMRT with conventional linac based plans, all created plans were clinically equivalent to current clinical practice. However, MRL-IMRT plans had higher dose to skin and larger low dose region of normal tissues. Furthermore, MRL-IMRT plans had significantly reduced optimization time by comparing conventional linac based plans. The number of MUs of MRL-IMRT was increased by 23% compared with ss-IMRT, and no difference from dMLC-IMRT. In conclusion, clinically acceptable plans can be achieved with 1.5 T MR-Linac system for multiple tumor sites. Given the differences in machine characteristics, some minor differences in plan quality were found between MR-Linac plans and current clinical practice and this should be considered in clinical practice.
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Harris, Richard, Rollo Sheldon, Jane McNulty, and Scott Cherry. "Improving the safety of rapid tranquilisation in older people." BJPsych Open 7, S1 (June 2021): S28. http://dx.doi.org/10.1192/bjo.2021.129.
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AimsTo identify intramuscular rapid tranquilisation (IMRT) events in all >65 years inpatients in Sussex Partnership NHS Foundation Trust (SPFT) and to establish whether accompanying documentation meets SPFT guidelines. This is a re-audit, initial data were collected in 2016. Multimodal intervention has been implemented since initial data collection. In psychiatric inpatients IMRT should be administered as a last resort to calm acutely disturbed patients after verbal de-escalation and an offer of oral medication has failed. IMRT can cause physical health complications and impact therapeutic relationships. Quality improvements made since initial data collection were: an IMRT treatment algorithm for >65s, a teaching package for staff, IMRT prescription area on medicine cards and post IMRT physical monitoring forms – in line with updates to trust IMRT policy.MethodRetrospective case note audit cycle of 119 patients. Electronic and paper records were reviewed for inpatients >65 years on 1/9/2019. Records were examined for instances of IMRT– the following features were noted: diagnosis; verbal de-escalation; oral medication offered prior to IMRT; IMRT prescription location; and post-IMRT monitoring. Descriptive statistics were performed. This audit was approved by the trust audit committee.ResultThere were 34 RT events in 17 patients, reduced from 83 RT events in 20 patients in 2016. De-escalation was attempted in 62% versus 34% in 2016, oral medication offered first in 71% versus 59% in 2016. Physical monitoring was fully completed in 50% of instances in 2019, an improvement from 23% in 2016.ConclusionEducation, a new treatment algorithm, medicine card changes, and IMRT physical monitoring forms have improved adherence to trust standards. There was a 49% reduction in IMRT events in 2019 versus 2016. De-escalation is being performed more frequently, and oral sedation offered in more cases. The physical monitoring of patients has improved.
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Welgemoed, Camarie, Simon Coughlan, Patti McNaught, Dorothy Gujral, and Pippa Riddle. "A dosimetric study to improve the quality of nodal radiotherapy in breast cancer." BJR|Open 3, no. 1 (January 2021): 20210013. http://dx.doi.org/10.1259/bjro.20210013.
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Objectives: Field-based planning for regional nodal breast radiotherapy (RT) used to be standard practice. This study evaluated a field-based posterior axillary boost (PAB) and two forward-planned intensity-modulated RT (IMRT) techniques, aiming to replace the first. Methods: Supraclavicular and axillary nodes, humeral head, brachial plexus, thyroid, and oesophagus were retrospectively delineated on 12 CT scans. Three plans, prescribed to 40.05 Gy, were produced for each patient. Breast plans consisted of field-in-field IMRT tangential fields in all three techniques. Nodal plans consisted of a field-based PAB (anterior and posterior boost beam), and 2 forward-planned techniques: simple IMRT 1 (anterior and posterior beam with limited segments), and a more advanced IMRT 2 technique (anterior and fully modulated posterior beam). Results: The nodal V90% was similar between IMRT 1: mean 99.5% (SD 1.0) and IMRT 2: 99.4% (SD 0.5). Both demonstrated significantly improved results (p = 0.0001 and 0.005, respectively) compared to the field-based PAB technique. IMRT 2 lung V12Gy and humeral head V10Gy were significantly lower (p = 0.002, 0.0001, respectively) than the field-based PAB technique. IMRT 1 exhibited significantly lower brachial plexus Dmax and humeral head V5, 10, and 15Gy doses (p = 0.007, 0.013, 0.007 and 0.007, respectively) compared to the field-based PAB technique. The oesophagus and thyroid dose difference between methods was insignificant. Conclusions: Both IMRT techniques achieved the dose coverage requirements and reduced normal tissue exposure, decreasing the risk of radiation side effects. Despite the increased cost of IMRT, compared to non-IMRT techniques 1, both IMRT techniques are suitable for supraclavicular and axillary nodal RT. Advances in knowledge: Forward-planned IMRT already resulted in significant dose reduction to organs at risk and improved planning target volume coverage. 1 This new, simplified forward-planned IMRT one technique has not been published in this context and is easy to implement in routine clinical practice.
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Prayongrat, Anussara, Chakkapong Chakkabat, Danita Kannarunimit, Pokrath Hansasuta, and Chawalit Lertbutsayanukul. "Prevalence and significance of plasma Epstein-Barr Virus DNA level in nasopharyngeal carcinoma." Journal of Radiation Research 58, no. 4 (February 14, 2017): 509–16. http://dx.doi.org/10.1093/jrr/rrw128.
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Abstract Epstein-Barr virus (EBV) DNA has been recognized as a promising tumor marker for nasopharyngeal carcinoma (NPC). This study aims to demonstrate the prevalence of plasma EBV DNA and its temporal correlation with treatment outcomes in the modern era. A total of 204 patients with Stage I–IVB NPC treated with intensity-modulated radiotherapy (IMRT) were enrolled. Quantitative plasma EBV DNA measurement was performed before treatment (pre-IMRT), on the fifth week of radiation (mid-IMRT), at 3 months after radiation (post-IMRT), then every 6 months until disease relapse. Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan–Meier method. Plasma EBV DNA was detected in 110 patients (53.9%), with a median pre-IMRT EBV DNA level of 8005 copies/ml. Significant correlation was noted between pre-IMRT EBV DNA level and disease stage, but not between pre-IMRT EBV DNA level and World Health Organization classification. With a median follow-up time of 35.1 months, the 3-year PFS and OS rates were higher in the group with undetectable pre-IMRT EBV DNA level compared with in the group in which it was detectable. When classified according to disease stage and pre-IMRT EBV DNA, patients with early disease and detectable pre-IMRT EBV DNA experienced poorer survival than those with locally advanced disease and undetectable pre-IMRT EBV DNA. According to the dynamic changes in EBV DNA level between pre-IMRT and mid/post IMRT, survival was significantly higher in patients who achieved an undetectable level following treatment. On multivariate analysis, post-IMRT EBV DNA level was the strongest predictor of all treatment outcomes (P < 0.001). Our study demonstrated the clinical significance of the plasma EBV DNA level at specific time points, as well as of the dynamic changes in the EBV DNA level. Disappearance of plasma EBV DNA after treatment was associated with better survival.
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Boer, Camilla Grindeland, Kristine Fjellanger, Inger Marie Sandvik, Maren Ugland, Grete May Engeseth, and Liv Bolstad Hysing. "Substantial Sparing of Organs at Risk with Modern Proton Therapy in Lung Cancer, but Altered Breathing Patterns Can Jeopardize Target Coverage." Cancers 14, no. 6 (March 8, 2022): 1365. http://dx.doi.org/10.3390/cancers14061365.
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Enhancing treatment of locally advanced non-small cell lung cancer (LA-NSCLC) by using pencil beam scanning proton therapy (PBS-PT) is attractive, but little knowledge exists on the effects of uncertainties occurring between the planning (Plan) and the start of treatment (Start). In this prospective simulation study, we investigated the clinical potential for PBS-PT under the influence of such uncertainties. Imaging with 4DCT at Plan and Start was carried out for 15 patients that received state-of-the-art intensity-modulated radiotherapy (IMRT). Three PBS-PT plans were created per patient: 3D robust single-field uniform dose (SFUD), 3D robust intensity-modulated proton therapy (IMPT), and 4D robust IMPT (4DIMPT). These were exposed to setup and range uncertainties and breathing motion at Plan, and changes in breathing motion and anatomy at Start. Target coverage and dose-volume parameters relevant for toxicity were compared. The organ at risk sparing at Plan was greatest with IMPT, followed by 4DIMPT, SFUD and IMRT, and persisted at Start. All plans met the preset criteria for target robustness at Plan. At Start, three patients had a lack of CTV coverage with PBS-PT. In conclusion, the clinical potential for heart and lung toxicity reduction with PBS-PT was substantial and persistent. Altered breathing patterns between Plan and Start jeopardized target coverage for all PBS-PT techniques.
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Balermpas, Panagiotis, Janita E. van Timmeren, David J. Knierim, Matthias Guckenberger, and Ilja F. Ciernik. "Dental extraction, intensity-modulated radiotherapy of head and neck cancer, and osteoradionecrosis." Strahlentherapie und Onkologie 198, no. 3 (January 14, 2022): 219–28. http://dx.doi.org/10.1007/s00066-021-01896-w.
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Abstract Objective To seek evidence for osteoradionecrosis (ORN) after dental extractions before or after intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC). Methods Medline/PubMed, Embase, and Cochrane Library were searched from 2000 until 2020. Articles on HNC patients treated with IMRT and dental extractions were analyzed by two independent reviewers. The risk ratios (RR) and odds ratios (OR) for ORN related to extractions were calculated using Fisher’s exact test. A one-sample proportion test was used to assess the proportion of pre- versus post-IMRT extractions. Forest plots were used for the pooled RR and OR using a random-effects model. Results Seven of 630 publications with 875 patients were eligible. A total of 437 (49.9%) patients were treated with extractions before and 92 (10.5%) after IMRT. 28 (3.2%) suffered from ORN after IMRT. ORN was associated with extractions in 15 (53.6%) patients, eight related to extractions prior to and seven cases related to extractions after IMRT. The risk and odds for ORN favored pre-IMRT extractions (RR = 0.18, 95% CI: 0.04–0.74, p = 0.031, I2 = 0%, OR = 0.16, 95% CI: 0.03–0.99, p = 0.049, I2 = 0%). However, the prediction interval of the expected range of 95% of true effects included 1 for RR and OR. Conclusion Tooth extraction before IMRT is more common than after IMRT, but dental extractions before compared to extractions after IMRT have not been proven to reduce the incidence of ORN. Extractions of teeth before IMRT have to be balanced with any potential delay in initiating cancer therapy.
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Hsieh, Chen-Hsi, Pei-Wei Shueng, Li-Ying Wang, Li-Jen Liao, Wu-Chia Lo, Hsin-Pei Yeh, Hsiu-Ling Chou, and Le-Jung Wu. "Single-Institute Clinical Experiences Using Whole-Field Simultaneous Integrated Boost (SIB) Intensity-Modulated Radiotherapy (IMRT) and Sequential IMRT in Postoperative Patients With Oral Cavity Cancer (OCC)." Cancer Control 27, no. 1 (January 1, 2020): 107327482090470. http://dx.doi.org/10.1177/1073274820904702.
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This study aimed to review clinical experiences using whole-field simultaneous integrated boost (SIB) intensity-modulated radiotherapy (IMRT) and sequential IMRT in postoperative patients with oral cavity cancer (OCC). From November 2006 to December 2014, a total of 182 postoperative patients with OCC who underwent either SIB-IMRT (n = 63) or sequential IMRT (n = 119) were enrolled retrospectively and matched randomly according to multiple risk factors by a computer. The differences were well balanced after patient matching ( P = .38). The median follow-up time was 65 months. For patients treated with the SIB technique and the sequential technique, the respective mortality rates were 36.8% and 20.0% ( P = .04). The primary recurrence rates were 26.3% and 10.0% ( P = .02), respectively. The respective marginal failure rates were 26.7% and 16.7%. A multivariate logistic regression analysis showed that patients who received the SIB technique had a 2.74 times higher risk of death than those who received the sequential technique (95% confidence interval = 1.10-6.79, P = .03). Sequential IMRT provided a significantly lower dose to the esophagus (5.2 Gy, P = .02) and trachea (4.6 Gy, P = .03) than SIB-IMRT. For patients with locally advanced OCC, postoperative sequential IMRT may overcome an unpredictable geographic miss, potentially with a lower marginal failure rate in the primary area. Patients treated by sequential IMRT show equal overall survival benefits to those treated by SIB-IMRT and a lower mortality rate than those treated by SIB-IMRT. Additionally, a reduced dose to the esophagus and trachea compared to sequential IMRT was noted.
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Raturi, Vijay P., Atsushi Motegi, Sadamoto Zenda, Naoki Nakamura, Hidehiro Hojo, Shin-Ichiro Kageyama, Masayuki Okumura, et al. "Comparison of a Hybrid IMRT/VMAT technique with non-coplanar VMAT and non-coplanar IMRT for unresectable olfactory neuroblastoma using the RayStation treatment planning system—EUD, NTCP and planning study." Journal of Radiation Research 62, no. 3 (April 12, 2021): 540–48. http://dx.doi.org/10.1093/jrr/rrab010.
Full textAbstract:
Abstract The purpose of this study was to compare hybrid intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (Hybrid IMRT/VMAT), with non-coplanar (nc) IMRT and nc-VMAT treatment plans for unresectable olfactory neuroblastoma (ONB). Hybrid IMRT/VMAT, nc-IMRT and nc-VMAT plans were optimized for 12 patients with modified Kadish C stage ONB. Dose prescription was 65 Gy in 26 fractions. Dose–volume histogram parameters, conformation number (CN), homogeneity index (HI), integral dose and monitor units (MUs) delivered per fraction were assessed. Equivalent uniform dose (EUD) and normal tissue complication probability (NTCP) based on the EUD model (NTCPLogit) and the Lyman–Kutcher–Burman model (NTCPLKB) were also evaluated. We found that the Hybrid IMRT/VMAT plan significantly improved the CN for clinical target volume (CTV) and planning treatment volume (PTV) compared with the nc-VMAT plan. In general, sparing of organs at risk (OARs) is similar with the three techniques, although the Hybrid IMRT/VMAT plan resulted in a significantly reduced Dmax to contralateral (C/L) optic nerve compared with the nc-IMRT plan. The Hybrid IMRT/VMAT plan significantly reduce EUD to the ipsilateral (I/L) and C/L optic nerve in comparison with the nc-IMRT plan and nc-VMAT plan, but the difference in NTCP between the three technique was <1%. We concluded that the Hybrid IMRT/VMAT technique can offer improvement in terms of target conformity and EUD for optic nerves, while achieving equal or better OAR sparing compared with nc-IMRT and nc-VMAT, and can be a viable radiation technique for treating unresectable ONB. However, the clinical benefit of these small differences in dosimetric data, EUD and NTCP of optic nerves may be minimal.
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Fredman, Elisha T., Aryavarta M. S. Kumar, and May Abdel-Wahab. "Comparing outcomes and toxicities from intensity-modulated radiation therapy and three-dimensional conformal radiation therapy for anal cancer: Is one really better?" Journal of Clinical Oncology 32, no. 3_suppl (January 20, 2014): 589. http://dx.doi.org/10.1200/jco.2014.32.3_suppl.589.
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589 Background: Intensity-modulated radiation therapy (IMRT) has largely supplanted 3-dimensional conformal radiation (3D-CRT) for definitive treatment of anal cancer due to its decreased toxicity and potentially improved outcomes. Convincing data directly demonstrating its advantages, however, remain limited. We compared outcomes, acute, and post-treatment toxicity of patients with anal cancer treated with concurrent chemotherapy and IMRT vs. 3D-CRT. Methods: We performed a single institution retrospective review of patients treated with IMRT or 3D-CRT as part of definitive Mitomycin-C/5-FU based chemoradiation for anal cancer from January 2003-December 2012. Results: 61 and 104 patients received IMRT and 3D-CRT respectively. Overall, 92.7% had squamous cell carcinoma. The mean pelvic dose before boost was 48.3Gy and 44Gy for IMRT and 3D-CRT respectively. Complete response, partial response, and disease progression rates were similar (83.6%, 8.2%, 8.2% for IMRT; 85.6%, 6.7%, 7.7% for 3D-CRT; p = ns). There was no significant difference in overall survival (p = 0.971), event free survival (p = 0.900), and local or distant recurrence rates (p = 0.118, p = 0.373). IMRT caused significantly less acute grade 1-2 incontinence (p = 0.035), grade 3-4 pain (p = 0.033) and fatigue (p = 0.030). Patients receiving IMRT had significantly fewer post-treatment toxicities (p = 0.008), outperforming 3D-CRT in 7/8 toxicities reviewed. Though total length of treatment was comparable between IMRT and 3D-CRT (43.6 and 44.5 days), the IMRT group had fewer, shorter treatment breaks (p = ns). Conclusions: This report represents the largest series directly comparing concurrent chemotherapy with IMRT vs. 3D-CRT for definitive treatment of anal cancer. IMRT significantly reduced acute and post-treatment toxicities and allowed for safe and effective pelvic dose escalation.
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Torres, Mylin A., Keerthi Gogineni, and David H. Howard. "Intensity-Modulated Radiation Therapy in Breast Cancer Patients Following the Release of a Choosing Wisely Recommendation." JNCI: Journal of the National Cancer Institute 112, no. 3 (October 24, 2019): 314–17. http://dx.doi.org/10.1093/jnci/djz198.
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Abstract In 2013, the American Society for Radiation Oncology recommended against the routine use of intensity-modulated radiation therapy (IMRT) in breast cancer patients. We evaluated trends in the use of IMRT before and after the release of the recommendation. Using Surveillance, Epidemiology, and End Results Medicare data, we identified 13 457 breast cancer patients diagnosed between 2012 and 2015 who received breast-conserving surgery and postsurgery, whole-breast, IMRT, or three-dimensional conformal radiotherapy. We find that the use of IMRT decreased by 4.6 (95% confidence interval [CI] = 3.6 to 5.6; two-sided P < .001) percentage points in hospital-based clinics. In freestanding radiotherapy clinics, which had baseline rates of IMRT use that were more than 20 percentage points higher than in hospital-based clinics, use of IMRT declined by 6.1 (95% CI = 3.5 to 8.7; two-sided P < .001) percentage points. Use of IMRT declined following the release of the recommendation, but a large share of patients treated in freestanding clinics continue to receive IMRT.
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Jain, Suneil, Patrick Cheung, D. Andrew Loblaw, Gerard Morton, Cyril Danjoux, Ewa Szumacher, William Chu, et al. "Comparison of acute toxicity in patients treated with a 4-field box or IMRT to deliver elective pelvic nodal irradiation for localized high-risk prostate cancer." Journal of Clinical Oncology 30, no. 5_suppl (February 10, 2012): 69. http://dx.doi.org/10.1200/jco.2012.30.5_suppl.69.
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69 Background: To deliver elective pelvic nodal irradiation (EPNI), a 4-field box (4FB) has been a common technique. More recently, there are increasing reports of using IMRT to deliver EPNI. Even though studies show a clear dosimetric benefit to bowel and bladder, there is a lack of good data demonstrating decreased toxicity with the use of IMRT in this setting. Methods: From 2004-2010, 230 patients with localized high risk prostate cancer were enrolled into 3 sequential prospective phase I/II trials of delivering EPNI (45 Gy) along with a concomitant hypofractionated IMRT boost to the prostate (67.5 Gy total) in 25 fractions over 5 weeks time. All patients were to receive 3 years of adjuvant androgen deprivation. During the accrual period, the method used to deliver the EPNI portion of the treatment changed as new literature emerged about target volumes for EPNI. The 3 methods used to deliver EPNI in this large cohort were 1) 4FB, 2) IMRT with 2cm CTV margins around the pelvic vessels as suggested by Shih et al (IMRT-Shih), and 3) IMRT with nodal volumes as suggested by RTOG (IMRT-RTOG). Common Terminology Criteria for Adverse Events v3.0 was used to assess acute toxicity prospectively during treatment and then at 3 months. Results: For EPNI, 94 patients were treated with a 4FB, 53 were treated with IMRT-Shih, and 83 were treated with IMRT-RTOG. There were no acute grade 3 GI toxicities. Patients in the 4FB group had higher rates of acute grade ≥ 2 proctitis compared to the IMRT-Shih and IMRT-RTOG groups (16.0% vs 2.0% vs 2.4%, p=0.0009). The 4FB group also had higher rates of grade ≥ 2 flatulence compared to the 2 other IMRT groups (17.0% vs 7.6% vs 0%, p<0.0001). With regards to acute GU toxicities, patients in the 4FB group had higher rates of grade ≥ 3 urinary frequency compared to the 2 other IMRT groups (5.3% vs 0% vs 0%, p=0.027). Conclusions: In this non-randomized comparison, IMRT resulted in statistically significant decreases in acute proctitis, flatulence, and urinary frequency when compared to a 4FB technique to deliver EPNI in localized high risk prostate cancer. Analysis for possible confounding factors will be performed.