PATRIOT Trial: Randomized phase II study of prostate stereotactic body radiotherapy comparing 11 versus 29 days overall treatment time.

6 Background: Stereotactic body radiotherapy (SBRT) for the treatment of prostate cancer is rapidly increasing. Reported regimens differ in time, dose, and fractionation. We report the results of a multicentre, Canadian randomized phase II study to investigate the impact of overall treatment time on quality of life (QOL) and toxicity. Methods: Men with cT1-2b, Gleason <=7, and PSA <= 20 ng/mL prostate cancer were randomly assigned to 40 Gy in 5 fractions delivered every other day (11 days) vs. once per week (29 days) using gantry-based SBRT. QOL was assessed using the Expanded Prostate Cancer Index Composite (EPIC) at baseline, weeks 2, 4, 6, 12, months 6 and 12, then annually. Toxicity was graded according to RTOG Criteria. The primary end point was the proportion of patients with a minimum clinically important change (MCIC) in bowel QOL at any time during the acute (<=12 week) period and was analyzed by Fisher’s exact test with a two-sided p < 0.05 considered significant. MCIC was defined as a decrease ...