LAUSR

96Background: To investigate the impact of 5-alpha-reductase inhibitors (5-ARIs) usage on radiotherapy outcomes for localized prostate cancer. Methods: From our institutional database of over 2500 patients, we identified 203 patients on a 5-ARI. They were all treated with either external beam radiotherapy (EBRT) or brachytherapy for localized prostate cancer. Patients receiving a 5-ARI were analyzed according to the following prostate cancer progression criteria: a) progression of Gleason score or increase in cancer volume on the biopsy, b) first biopsy positive for cancer after being treated for urinary symptoms with a 5-ARI, and c) prostate-specific antigen (PSA) progression with or without a previous cancer diagnosis. Biochemical failure (BF) was defined by the Phoenix definition. Log-rank test was used for survival analysis. Results: At a median follow-up of 36 months (interquartile range [IQR] 22-52 months), 10 (4.9%) patients experienced BF. 52% of men demonstrated none of the progression criteria, ...