Four-weeks versus 5-weeks hypofractionated high dose radiotherapy as primary therapy for prostate cancer: interim safety analysis of a randomized phase 3 trial
Mené sur 160 patients atteints d'un cancer de la prostate, cet essai de phase III évalue, en fonction de la dose de rayonnements administrée et de la durée d'administration, la toxicité d'une radiothérapie hypofractionnée en traitement de première ligne
Methods and Materials : Between 6/2013 and 7/2016, 160 PC patients were randomly assigned (1:1) within this single centre phase 3 trial, to 56 Gray (Gy) (16x3.5Gy, Arm A) or 67 Gy (25x2.68Gy, Arm B). Randomization was by computer-generated permuted blocks, stratified on prior transurethral resection of the prostate and presence of a dominant intraprostatic lesion. Treatment allocation was not masked. Clinicians were not blinded. The primary endpoint is acute gastro-intestinal (GI) toxicity, assessed by CTC version 4.0 and RTOG. An interim analysis on acute toxicity was planned on 160 patients to prove the safety of both treatment regimens. If ≥22/72 patients have grade ≥2 GI toxicity, the study arm is to be rejected. The study is registered on Clinicaltrials.gov (NCT01921803). Results : In Arm A, 20 (26%) and 1 (1%) patients developed acute grade 2 and grade 3 GI toxicity. In Arm B, 16 (20%) reported acute grade 2 GI toxicity. In Arm A, 42 (55%) and 5 (6%) patients developed acute grade 2 and grade 3 urinary toxicity. In Arm B, 40 (49%) and 7 (9%) reported acute grade 2 and grade 3 urinary toxicity. Toxicity peaked during radiotherapy resolving in the months following radiotherapy. Conclusion : With acute grade ≥2 GI toxicity reported in 21/77 patients in Arm A and 16/82 patients in Arm B, both treatment arms are considered safe.