Hypofractionated, Dose Escalation Radiotherapy For High-Risk Prostate Cancer: The Primary Endpoint Of A Group Led Phase Iii Trial. (Pcs5).

123Background: The low αβ ratio of prostate cancer (PCa), 1.5-2, suggests high radiation-fraction sensitivity and predicts a therapeutic advantage of hypofractionated radiation treatment (HFRT). Most available data of moderate HFRT have focused on low, intermediate and/or mixed risk groups. We therefore conducted the first randomized trial of moderately HFRT in high-risk PCa patients and present the primary safety analysis of side effects at 2 years. Methods: We conducted a Canadian multi-centric phase III trial of conventional fractionated radiation therapy (CFRT) vs. intensity-modulated HFRT in men with high-risk PCa as per NCCN definition. From February 2012 to March 2015, 329 patients were randomized in a 1:1 ratio to receive either CFRT or HFRT. All patients received neo-adjuvant, concurrent and adjuvant androgen suppression, with a median duration of 24 months. CFRT consisted of 76 Gy in 2 Gy per fraction to the prostate where 46 Gy was delivered to the pelvic lymph nodes. HFRT consisted of concomi...