Dose-Volume Constraints to Reduce Rectal Side Effects From Prostate Radiotherapy: Evidence From MRC RT01 Trial ISRCTN 47772397
- Department of Radiation Oncology, Illawarra Cancer Care Centre, Wollongong Hospital, NSW (Australia)
- Cancer Group, Medical Research Council Clinical Trials Unit, London (United Kingdom)
- Department of Medical Physics, Mount Vernon Hospital, Northwood (United Kingdom)
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton (United Kingdom)
- Atomic Weapons Establishment, Aldermaston (United Kingdom)
- Tomotherapy Inc., Culliganlaan, Diegem (Belgium)
- Department of Physics, Clatterbridge Centre for Oncology, Wirral (United Kingdom)
- Servicio de Radioterapia, Clinica Alemana de Santiago, Santiago (Chile)
- Department of Academic Urology, Institute of Cancer Research and Royal Marsden Hospitals, Sutton (United Kingdom)
Purpose: Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (>=50 Gy). Evidence is emerging that lower doses could also be important. Methods and Materials: Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity. Results: A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30<=80%, V40<=65%, V50<=55%, V60<=40%, V65<=30%, V70<=15%, and V75<=3%. Conclusion: Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity.
- OSTI ID:
- 21372096
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2009.02.025; PII: S0360-3016(09)00254-5; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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