Four-year outcomes of hypofractionated proton therapy for localized prostate cancer.

80Background: Hypofractionated radiation therapy (HFRT) is an effective treatment for localized prostate cancer (LPC). This study was performed to determine the toxicity profile and biochemical-clinical failure (BCF) rates for patients with LPC treated with hypofractionated proton therapy (HFPT). Methods: Between 2010 and 2017, 184 men were enrolled on a trial of 70Gy in 28 fractions of HFPT for low to intermediate-risk LPC. Androgen suppression (AS) was allowed. Acute and late toxicity was evaluated using the Common Terminology Criteria for Adverse Events, version 4.0. Urinary and erectile quality of life changes were captured using the International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF-5) Questionnaire, respectively. Results: Median follow-up was 49.2 months. Enrolled patients had low-risk [LR] (n = 18), favorable intermediate-risk [FIR] (n = 78), and unfavorable intermediate-risk [UIR] (n = 88) disease. Twenty-six percent of patients received neoadjuvant ...