Academic literature on the topic 'Radiotherapy fractionation schemes'
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Journal articles on the topic "Radiotherapy fractionation schemes":
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Unkelbach, Jan, Dávid Papp, Melissa R. Gaddy, Nicolaus Andratschke, Theodore Hong, and Matthias Guckenberger. "Spatiotemporal fractionation schemes for liver stereotactic body radiotherapy." Radiotherapy and Oncology 125, no. 2 (November 2017): 357–64. http://dx.doi.org/10.1016/j.radonc.2017.09.003.
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Antunac, Katarina, and Lidija Beketić-Orešković. "Breast cancer radiotherapy - changes in fractionation schemes through decades." Libri Oncologici Croatian Journal of Oncology 51, no. 1 (June 27, 2023): 20–24. http://dx.doi.org/10.20471/lo.2023.51.01.03.
Abstract:
Traditionally, as a standard dose fractionation schedule, adjuvant radiotherapy for breast cancer has been performed using prescribed doses of 46–50 Gy divided into daily fractions of 1.8–2 Gy. Overall, radiotherapy treatment took 5 weeks. In the 1990s, schedules using higher daily doses (2.5–3 Gy), a smaller number of fractions (hypofractionation), and a reduced overall prescribed dose started in the context of clinical trials. First results revealed an equivalent cosmetic effect of hypofractionated protocols compared to standard fractionation, and after longer follow-up, hypofractionation was connected with better control of the disease. Hypofractionation started to be considered the new treatment standard. Results of newer clinical trials confirm the efficacy and safety of adjuvant breast cancer radiotherapy lasting 5 working days using daily fractions of 5.2 Gy in certain subgroups of breast cancer patients.
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Valdagni, Riccardo. "Altered Fractionation in Radiotherapy." Tumori Journal 84, no. 2 (March 1998): 155–59. http://dx.doi.org/10.1177/030089169808400211.
Abstract:
Differences between late-responding (slowly proliferating) normal tissues and early-responding (rapidly proliferating) normal tissues and tumor cells and the event of tumor cell repopulation occurring during treatment have essentially led to the development of altered fractionation schemes. Altered fractionation regimens mainly refer to schedules utilising two or more (small dose) fractions per day for part of or for the entire treatment course. It must be underlined that a true standard or conventional fractionation regimen does not exist: no schedule is universally recognised as the standard of reference to be compared with. However, continental European and U.S. conventional regimens are the considered control arm with which the new experimental regimens have to be compared. For this reason they are generally recognised as the standards. The basic rationale for hyperfractionated or accelerated regimens respectively lies in the possibility (a) to deliver higher total doses reducing late-responding normal tissue damage, (b) to deliver total doses in a reduced overall treatment time to defeat tumor clonogen repopulation. Multiple fractions per day should not be delivered with interfraction intervals smaller than 6 hours. Clinical results of phase I-II and limited but convincing phase III randomised trials suggest that a therapeutic benefit can be achieved with new altered regimens.
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Kuznetsov, Maxim, and Andrey Kolobov. "Optimization of Dose Fractionation for Radiotherapy of a Solid Tumor with Account of Oxygen Effect and Proliferative Heterogeneity." Mathematics 8, no. 8 (July 22, 2020): 1204. http://dx.doi.org/10.3390/math8081204.
Abstract:
A spatially-distributed continuous mathematical model of solid tumor growth and treatment by fractionated radiotherapy is presented. The model explicitly accounts for three time and space-dependent factors that influence the efficiency of radiotherapy fractionation schemes—tumor cell repopulation, reoxygenation and redistribution of proliferative states. A special algorithm is developed, aimed at finding the fractionation schemes that provide increased tumor cure probability under the constraints of maximum normal tissue damage and maximum fractional dose. The optimization procedure is performed for varied radiosensitivity of tumor cells under the values of model parameters, corresponding to different degrees of tumor malignancy. The resulting optimized schemes consist of two stages. The first stages are aimed to increase the radiosensitivity of the tumor cells, remaining after their end, sparing the caused normal tissue damage. This allows to increase the doses during the second stages and thus take advantage of the obtained increased radiosensitivity. Such method leads to significant expansions in the curative ranges of the values of tumor radiosensitivity parameters. Overall, the results of this study represent the theoretical proof of concept that non-uniform radiotherapy fractionation schemes may be considerably more effective that uniform ones, due to the time and space-dependent effects.
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Fallai, Carlo, and Patrizia Olmi. "Altered Fractionation Schedules in Radiotherapy of Head and Neck Cancer. A Review." Tumori Journal 78, no. 5 (October 1992): 311–25. http://dx.doi.org/10.1177/030089169207800506.
Abstract:
The authors review the main contributions of international literature to show the current status in clinical trials on unconventional fractionations of the dose in radiotherapy of head and neck cancers. Several clinical (but only a few randomized) trials have been conducted over the last 15 years using hyperfractionated (HF), accelerated (AF) or mixed (HF-AF) schedules. HF schedules have obtained promising results in terms of local control in comparison with conventional fractionation (CF) of the dose. Improvement in survival was also obtained by the random trials of Pinto and Sanchiz, whereas in EORTC trial no. 22791, the improvement in survival rate was only marginal. A significant increase in local control and, less frequently, in survival has been claimed in several studies using HF-AF. Such data still need to be confirmed by a random study, since EORTC trial 22811 showed superimposable results in comparison with CF. Selection of the most suitable cases for altered fractionation schemes is also being studied in ongoing trials of the EORTC (22851) and RTOG (90-03). As regards acute reactions during and after altered fractionation, they are more severe than after CF. Only pure HF with a dose intensity approximately comparable to CF seems to produce similar acute reactions. Several factors have been found to influence the severity of acute mucosal reactions: interfraction interval, overall treatment time, total dose, and field size. As regards late damage, genuine HF schemes seem to cause roughly equivalent late damage in comparison to CF, whereas high-dose intensity schedules have a higher rate of complications. Interfraction interval, overall treatment time, total dose, fraction size and field size can influence the risk of late sequelae. Before altered fractionations can be considered standard therapy, more data are needed, which should be provided by multicentric randomized trials, some of which are already in progress.
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Joseph, Nuradh, Norman F. Kirkby, Peter J. Hoskin, Catharine M. L. West, Ananya Choudhury, and Roger G. Dale. "Radiobiologically derived biphasic fractionation schemes to overcome the effects of tumour hypoxia." British Journal of Radiology 93, no. 1112 (August 2020): 20190250. http://dx.doi.org/10.1259/bjr.20190250.
Abstract:
Objective: As a fractionated course of radiotherapy proceeds tumour shrinkage leads to resolution of hypoxia and the initiation of accelerated proliferation of radioresistant cancer cells with better repair capacity. We hypothesise that, in tumours with significant hypoxia, improved tumour control could be achieved with biphasic fractionation schedules that either use acceleration after 3–4 weeks of conventional radiotherapy or deliver a higher proportional dose towards the end of a course of treatment. We conducted a modelling study based on the concept of biological effective dose (BED) comparing such novel regimens with conventional fractionation. Methods: The comparator conventional fractionation schedule 70 Gy in 35 fractions delivered over 7 weeks was tested against the following novel regimens, both of which were designed to be isoeffective in terms of late normal tissue toxicity. 40 Gy in 20 fractions over 4 weeks followed by 22.32 Gy in 6 consecutive daily fractions (delayed acceleration) 30.4 Gy in 27 fractions over 4 weeks followed by 40 Gy in 15 fractions over 3 weeks (temporal dose redistribution) The delayed acceleration regimen is exactly identical to that of the comparator schedule over the first 28 days and the BED gains with the novel schedule are achieved during the second phase of treatment when reoxygenation is complete. For the temporal redistribution regimen, it was assumed that the reoxygenation fraction progressively increases during the first 4 weeks of treatment and an iterative approach was used to calculate the final tumour BED for varying hypoxic fractions. Results: Novel fractionation with delayed acceleration or temporal fractionation results in tumour BED gains equivalent to 3.5–8 Gy when delivered in 2 Gy fractions. Conclusion: In hypoxic tumours, novel fractionation strategies result in significantly higher tumour BED in comparison to conventional fractionation. Advances in knowledge: We demonstrate that novel biphasic fractionation regimens could overcome the effects of tumour hypoxia resulting in biological dose escalation.
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Chalimou, Ioanna, Helena Lind, Georgios C. Sakellaropoulos, Bengt K. Lind, Nikos Papanikolaou, Georgios C. Nikiforidis, and Panayiotis Mavroidis. "Clinical survey for registering treatment decision criteria in advanced non-small-cell lung cancer radiotherapy and determination of the dose–response relationship for 1-year survival." Journal of Radiotherapy in Practice 13, no. 1 (April 22, 2013): 18–28. http://dx.doi.org/10.1017/s1460396912000519.
Abstract:
AbstractPurposeRecent studies have suggested significant variations in radiotherapy schedules used to treat advanced non-small-cell lung cancer (NSCLC), both between different centers in one country as well as between countries. In this study, different treatment methodologies have been explored using management plans proposed by radiation oncologists regarding general questions and theoretical case histories for patients with advanced NSCLC.Materials and methodsThe survey was conducted by sending a questionnaire to 24 radiotherapy centers in Europe. The questionnaire was composed of two sections. The first section concerned reasons for giving radiotherapy, parameters that influence the choice of total dose and fractionation for radiotherapy and kind of equipment used. The second section concerned the management of five theoretical patients (A–E) regarding the selection of the radiotherapy technique and the aim of treatment (radical or palliative). Furthermore, 19 trials comparing different regimens of palliative radiotherapy in patients with NSCLC were reviewed. There were marked differences in the doses of the investigated radiotherapy schemes, the patient characteristics and the assessed outcome measures.Results70% of the responders answered that the most important factors for deciding what dose and fractionation scheme to use were: metastases, performance status (PS) of the patient, lung function and size of the primary tumour. The most common reasons for giving the treatment were symptom relief, prolongation of life and, in some cases, possibly cure. More than 95% of the responders stated that they would give radiotherapy in each of these cases. The total doses proposed where 20 Gy in five fractions or 30 Gy in ten fractions in 2 weeks for the cases A and D. If the previous two schemes were converted to a fractionation scheme delivering 2 Gy per fraction, the equivalent doses would be 23 and 33 Gy, respectively. For the cases B, C and E, the proposed fractionation schemes were 2 Gy daily to 60–68 Gy in 6 weeks or 2 Gy daily to 68 Gy in 7 weeks. For the case E, 20% of the responders suggested Stereotactic Body Radiotherapy (SBRT) giving 21 Gy three times a week with a day apart to 63 Gy. The total dose and number of fractions of radiotherapy are related to the perceived aims and expectations of treatment. Those aiming at extending life would give significantly higher total doses in a larger number of fractions, whereas those aiming at relieving symptoms would give significantly lower total doses. There is evidence for an increase in survival, in patients who are given higher radiotherapy doses, especially in those patients with better PS.ConclusionsThis survey demonstrates a range of treatment strategies for advanced and inoperable NSCLC within Europe. There are a number of factors that influence the perceived aims of treatment and treatment planning. These factors should be taken into account when evaluating the effectiveness of different irradiation techniques, especially in the determination of radiobiological parameters and dose–response relations. The majority of patients should be treated with short courses of palliative radiotherapy, of one or two fractions. The use of high-dose palliative regimens using many fractions or SBRT should be considered for selected patients with good PS.
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Unkelbach, J., D. Papp, M. Gaddy, N. Andratschke, T. Hong, and M. Guckenberger. "PO-0900: Spatiotemporal fractionation schemes for liver stereotactic body radiotherapy." Radiotherapy and Oncology 127 (April 2018): S479—S480. http://dx.doi.org/10.1016/s0167-8140(18)31210-6.
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Dudley, Sara, Yushen Qian, Aadel Chaudhuri, Kiran Kumar, Sonya Aggarwal, and Daniel Tandel Chang. "Survival comparison of patients treated with one versus five fraction palliative radiotherapy." Journal of Clinical Oncology 33, no. 29_suppl (October 10, 2015): 200. http://dx.doi.org/10.1200/jco.2015.33.29_suppl.200.
Abstract:
200 Background: Choice of fractionation scheme for palliative radiotherapy has received greater attention in recent years, particularly in the current healthcare environment where issues of cost and quality of life have taken on increasing importance. The ASTRO Choosing Wisely campaign recommends against routine use of extended fractionation schemes ( > 10 fractions) for palliation of bone metastases given equivalent pain relief between 30 Gy in 10 fractions and 8 Gy in 1 fraction, and strong consideration for use of 8 Gy in 1 fraction is urged for patients with a limited prognosis or transportation difficulties. We investigated whether there was a difference in survival between patients treated with an intermediate fractionation scheme (5 fractions) and patients who received single-fraction treatment. Methods: We identified 220 patients who received a total of 264 courses of palliative radiotherapy with either 8 Gy in 1 fraction (n = 91) or 20 Gy in 5 fractions (n = 173). Date of death was obtained from either the patient’s medical record, the Social Security Death Index, or publicly available obituaries. If none of these yielded a date of death, patients were censored at the date of their last clinical encounter. The majority of patients (n = 192) were treated for bone metastases. All primary sites were included, with the three most common histologies being lung, breast and prostate (n = 80, 31 and 16, respectively). Results: Overall, we found no significant survival difference between the two groups. Patients treated with 8 Gy in 1 fraction had a median survival of 146 days, whereas patients treated with 20 Gy in 5 fractions had a median survival of 183 days (p = 0.43). Conclusions: Given no difference in survival between fractionation schemes of 20 Gy in 5 fractions and 8 Gy in 1 fraction, delivery of palliative radiation in a single fraction should be strongly considered. Previous studies have identified a higher re-treatment rate in single-fraction treatments, although closer analysis of this data revealed no difference in absolute pain scores prior to re-treatment. Thus, re-treatment for single-fraction radiotherapy may be due instead to a greater clinical willingness to re-treat as opposed to a greater clinical need.
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Unkelbach, Jan, Chuan Zeng, and Martijn Engelsman. "Simultaneous optimization of dose distributions and fractionation schemes in particle radiotherapy." Medical Physics 40, no. 9 (August 5, 2013): 091702. http://dx.doi.org/10.1118/1.4816658.
Dissertations / Theses on the topic "Radiotherapy fractionation schemes":
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Hami, Abdoul-Azize Rihab. "Simulation des processus radiobiologiques basés sur l'imagerie pour l'évaluation de schémas thérapeutiques individualisés en radiothérapie." Electronic Thesis or Diss., Brest, 2024. http://www.theses.fr/2024BRES0002.
Abstract:
La radiothérapie est l'un des principaux traitements du cancer. Malgré son utilisation intensive en pratique clinique, son efficacité dépend de plusieurs facteurs. Plusieurs études ont montré que la réponse tumorale à la radiothérapie diffère d'un patient à l'autre. En effet, la réponse de la tumeur est influencée par plusieurs facteurs comme l'hypoxie et des multiples interactions entre le microenvironnement tumoral et les cellules saines. Cinq concepts biologiques majeurs appelés les « 5 Rs » qui résument ces interactions ont vu le jour. Ces concepts incluent la réoxygénation, la réparation cellulaire, la redistribution cellulaire dans le cycle, la radiosensibilité intrinsèque et la repopulation tumorale. La stratégie de traitement optimale doit tenir compte de ces « 5 Rs ». Dans cette étude, nous avons proposé dans un premier temps une approche de modélisation d'oxygénation qui peut être considérée comme un processus d'optimisation de traitement en absence de données concernant l'oxygène. Nous avons utilisé un modèle multi-échelle afin de prédire les effets de la radiothérapie sur la croissance tumorale en utilisant une base des images de tomographie par émission de positons (PET). Ensuite, nous avons inclus dans notre modèle les «5 Rs » de la radiothérapie, afin de prédire les effets des rayonnements sur la croissance tumorale. Enfin, nous avons présenté une étude sur l'effet de différents types de fractionnement sur la réponse tumorale à la radiothérapieRadiotherapy is one of the principal cancer treatments. Despite its intensive use in clinical practice, itseffectiveness depends on several factors. Several studies showed that the tumor response to radiotherapy differ from one patient to another. The response of tumor is influenced by several factors like hypoxia and multiple interactions between the tumor microenvironment and healthy cells. Five major biologic concepts called “5 Rs” resume these interactions. These concepts include reoxygenation, DNA damage-repair, cell cycle redistribution, cellular radiosensitivity and cellular repopulation.The optimal treatment strategy must consider these “5 Rs". In this study, we proposed as a first an approach to oxygenation modeling that can be considered as an optimization process in the absence of data concerning oxygen. We used a multi-scale model to predict the effects of radiotherapy on tumor growth based on information extracted from positron-emission tomography (PET) images. Then, we included to our model the ‘’5 Rs’’ of radiotherapy, to predict the effects of radiation on tumor growth. Finally, we presented a study of the effect of different types of fractionations on tumor response to radiotherapy
Book chapters on the topic "Radiotherapy fractionation schemes":
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Stuschke, Martin, and Christoph Pöttgen. "Altered Fractionation Schemes in Radiotherapy." In Frontiers of Radiation Therapy and Oncology, 150–56. Basel: KARGER, 2009. http://dx.doi.org/10.1159/000262470.
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Unkelbach, J. "Non-uniform spatiotemporal fractionation schemes in photon radiotherapy." In IFMBE Proceedings, 401–4. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19387-8_97.
Conference papers on the topic "Radiotherapy fractionation schemes":
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Batra, Ankit. "Clinical comparison of toxicity pattern of two linear quadratic model-baesd fractionation schemes of high-dose-rate intracavitary brachytherapy for cervical cancer." In 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685255.
Abstract:
Introduction: Carcinoma cervix is the fourth (GLOBACON 2012) most common cancer among women worldwide, and the main cancer affecting women in Sub-Saharan Africa, Central America and south-central Asia. In India, approx. 1,23,000 (GLOBACON 2012) new cases of carcinoma cervix are diagnosed each year. Brachytherapy is an integral part of treatment of cancer cervix. In the context of a developing country like us where maximum utilization of the resource is of prime importance to provide treatment to the large patient cohort, shortening the treatment duration and number of fractions always increases efficiency. In order to maximize the logistic benefits of HDR-BT while improving patient compliance and resource sparing, various fractionation regimens are used. Fractionation and dose adjustments of the total dose are radiobiologically important factors in lowering the incidence of complications without compromising the treatment results. Aim: To compare patient outcomes and complications using two linear-quadratic model-based fractionation schemes of high-dose-rate intracavitary brachytherapy (HDR-IC) used to treat cervical cancer. Materials and Methods: A prospective randomized study on 318 patients, with histologically proven advanced carcinoma cervix (stages IIB-IIIB) was enrolled in the study. All patients received External Beam Radio Therapy (EBRT) 50 Gy in 25 fractions with concurrent chemotherapy (cisplatin 35 mg/m2) followed by IntraCavitary brachytherapy using high dose rate equipment. Patients were randomised after completion of EBRT into two arms: (1) Arm 1: HDR ICRT 6.5 Gy per fraction for 3 fractions, a week apart. (2) Arm 2: HDR ICRT, 9 Gy per fraction for 2 fractions, 1 week apart. On completion of treatment, patients were assessed monthly for 3 months followed by 3 monthly thereafter. Treatment response was assessed according to WHO criteria after one month of completion of radiotherapy. The RTOG criteria were used for radiation induced toxicities. We analyzed late toxicities in terms of Rectal, Bladder, Small Bowel toxicity and Vaginal Stenosis. Results: Acute reactions in both the groups were comparable. None of the patient developed Grade 4 toxicity in our study and no toxicity related mortality was encountered. A slightly high frequency of late toxicity was observed in 9Gy Arm patients but was not statistically significant. Conclusion: In our setup, HDR brachytherapy at 9 Gy per fraction in two fractions is safe, effective and resource saving method with good local control, survival, and manageable normal tissue toxicity.
Reports on the topic "Radiotherapy fractionation schemes":
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Skelly, Andrea C., Eric Chang, Jessica Bordley, Erika D. Brodt, Shelley Selph, Rongwei Fu, Rebecca Holmes, et al. Radiation Therapy for Metastatic Bone Disease: Effectiveness and Harms. Agency for Healthcare Research and Quality (AHRQ), August 2023. http://dx.doi.org/10.23970/ahrqepccer265.
Abstract:
Objectives. To evaluate the comparative effectiveness and harms of external beam radiation therapy (EBRT) for palliative treatment of metastatic bone disease (MBD). Data sources. Four electronic databases from 1985 to January 30, 2023; a targeted search for re-irradiation through January 30, 2023; reference lists; and a Federal Register notice. Review methods. Using predefined criteria and dual review, we selected randomized controlled trials (RCTs) and nonrandomized studies of interventions (NRSIs) comparing dose-fractionation schemes and EBRT delivery techniques (for initial radiation and re-irradiation, i.e., retreatment for recurrent or persistent pain) and EBRT alone versus in combination with other palliative treatments. Study risk of bias was assessed using predefined criteria. Strength of evidence (SOE) was assessed for the primary outcomes of pain, function, spinal cord compression relief, quality of life, and harms. Results. We included 53 RCTs and 31 NRSIs; most were fair quality. In patients receiving initial radiation for MBD there was a small increase in the likelihood of overall pain response (improved pain measures with stable or decreased analgesic use) for multiple fraction (MF) EBRT versus single fraction (SF) EBRT up to 4 weeks post-radiation therapy (SOE: moderate) and for higher dose (6 or 8 Gy) SF EBRT versus lower dose (4 Gy) SF EBRT up to 52 weeks post-radiation therapy (SOE: low). SF and MF EBRT did not differ at later followup (SOE: moderate) nor did comparisons of MF EBRT dose/fractions (SOE: moderate ≤12 weeks; low >12 weeks). Re-irradiation was more common with SF versus MF EBRT. Stereotactic body radiation therapy (SBRT) (SF or MF) was associated with a slightly higher (up to 20 weeks, SOE: low) and moderately higher (30 weeks; SOE: moderate) likelihood of overall pain response versus MF EBRT. For re-irradiation, SF and MF SBRT had a similar likelihood of overall pain response, as did SF versus MF EBRT (SOE: low for all). Harms may be similar across dose/fraction schemes and techniques; serious harms were rare. Comparative effectiveness evidence for EBRT was sparse. Conclusions. In patients with uncomplicated MBD receiving initial palliative radiotherapy, the likelihood of overall pain response for SF and MF EBRT is probably similar, particularly after 4 weeks; re-irradiation was more common with SF-EBRT. SF and MF SBRT may provide slightly greater likelihood of overall pain response versus MF EBRT; evidence is limited. SF and MF EBRT may have similar likelihoods of overall pain response in patients receiving re-irradiation. High-quality evidence comparing SBRT with EBRT is needed in populations with complicated and uncomplicated MBD, as is research on effectiveness of EBRT versus other treatments. Update: An addendum is located at the end of the main report, before the appendixes.