Anorectal dose–effect relations for late gastrointestinal toxicity following external beam radiotherapy for prostate cancer in the FLAME trial
Publication date
2021-09
Authors
Groen, Veerle H.
Zuithoff, NPA
van Schie, Marcel
Monninkhof, E M
Kunze-Busch, Martina
de Boer, J C J
van der Voort van Zyp, J. R N
Pos, Floris J.
Smeenk, Robert Jan
Haustermans, Karin
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Article
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Abstract
BACKGROUND AND PURPOSE: The phase III FLAME trial (NCT01168479) showed an increase in five-year biochemical disease-free survival, with no significant increase in toxicity when adding a focal boost to external beam radiotherapy (EBRT) for localized prostate cancer [Kerkmeijer et al. JCO 2021]. The aim of this study was to investigate the association between delivered radiation dose to the anorectum and gastrointestinal (GI) toxicity (grade ≥2). MATERIAL AND METHODS: All patients in the FLAME trial were analyzed, irrespective of treatment arm. The dose-effect relation of the anorectal dose parameters (D2cm 3 and D50%) and GI toxicity grade ≥2 in four years of follow-up was assessed using a mixed model analysis for repeated measurements, adjusted for age, cardiovascular disease, diabetes mellitus, T-stage, baseline toxicity grade ≥1, hormonal therapy and institute. RESULTS: A dose-effect relation for D2cm 3 and D50% was observed with adjusted odds ratios of 1.17 (95% CI 1.13-1.21, p < 0.0001) and 1.20 (95% CI 1.14-1.25, p < 0.0001) for GI toxicity, respectively. CONCLUSION: Although there was no difference in toxicity between study arms, a higher radiation dose to the anorectum was associated with a statistically significant increase in GI toxicity following EBRT for prostate cancer. This dose-effect relation was present for both large and small anorectal volumes. Therefore, further increase in dose to the anorectum should be weighed against the benefit of focal dose escalation for prostate cancer.
Keywords
Anorectal dose parameters, Dose-effect relations, External beam radiotherapy, Focal boosting, Gastrointestinal toxicity, Prostate cancer, Radiotherapy Dosage, Prostatic Neoplasms/radiotherapy, Humans, Clinical Protocols, Male, Gastrointestinal Diseases/etiology, Disease-Free Survival, Brachytherapy, Hematology, Oncology, Radiology Nuclear Medicine and imaging, Journal Article, Research Support, Non-U.S. Gov't, Clinical Trial, Phase III
Citation
Groen, V H, Zuithoff, N P A, van Schie, M, Monninkhof, E M, Kunze-Busch, M, de Boer, H C J, van der Voort van Zyp, J, Pos, F J, Smeenk, R J, Haustermans, K, Isebaert, S, Draulans, C, Depuydt, T, Verkooijen, H M, van der Heide, U A & Kerkmeijer, L G W 2021, 'Anorectal dose–effect relations for late gastrointestinal toxicity following external beam radiotherapy for prostate cancer in the FLAME trial', Radiotherapy and Oncology, vol. 162, pp. 98-104. https://doi.org/10.1016/j.radonc.2021.06.033