Four-weeks versus 5-weeks hypofractionated high dose radiotherapy as primary therapy for prostate cancer: interim safety analysis of a randomized phase 3 trial

Publication date: Available online 19 December 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): V. Fonteyne, C. Sarrazyn, M. Swimberghe, G. De Meerleer, E. Rammant, B. Vanderstraeten, Frank Vanpachtenbeke, N. Lumen, K. Decaestecker, Roos Colman, G. Villeirs, P. Ost
PurposeHypofractionated radiotherapy (HFRT) for localised prostate cancer (PC) is safe and effective. The question remains which hypofractionation schedule to implement.In this study 2 different HFRT regimens are compared.Methods and MaterialsBetween 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).ResultsIn 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.resultsIn 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.ConclusionWith 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.conclusion

Teaser

In this randomised phase 3 trial the incidence in toxicity of 2 different hypofractionated radiotherapy regimens is evaluated. This pre-planned safety interim analysis confims that both regimens are safe and that the study can be continued.


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