Comparison of AUA and phoenix definitions of biochemical failure following permanent brachytherapy for prostate cancer

PURPOSE: To compare biochemical recurrence free survival (BCRFS) and cancer-specific survival (CSS) after brachytherapy using the AUA and the Phoenix definitions. METHODS AND MATERIALS: 2634 men with T1-T4N0M0 prostate cancer were treated with brachytherapy with or without neoadjuvant hormonal therapy or external beam radiation therapy. Five, 10, and 15-year BCRFS and CSS were estimated with Kaplan-Meier estimates with log rank. Multivariate analysis of survival was performed with Cox regression analysis. RESULTS: Median age was 66, follow-up was 8.6 years, and prostate specific antigen was 6.9. Overall, 11.1% (n = 293) of patients experienced Phoenix BCR and 17.48% (n = 457) experienced AUA BCR. The rates of AUA BCR and Phoenix BCR were significantly different at 5 and 10-years but not at 15 years. Patients treated with BED <= 200 Gy were more likely to experience AUA BCR (22.5% vs. 12.4%, OR 1.44, p < 0.001) and Phoenix BCR (14.3% and 8.3%, OR 1.37, p < 0.001) than patients treated with a BED > 200 Gy. CONCLUSIONS: Compared to the Phoenix definition, the AUA definition of BCR after brachytherapy is associated with significantly worse BCRFS for the first 15 years after treatment. Receiving a BED > 200, which cannot be achieved without the addition of brachytherapy, is associated with better BCRFS and CSS. Our findings reaffirm the importance of dose in the management of prostate cancer (c) 2022 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.