BRCA carrier status as an independent prognostic factor associated with earlier biochemical relapse in local prostate cancer.

Abstract

1545 Background: Biochemical relapse after local treatment for prostate cancer (PCa) indicates recurrent disease and is associated with shorter survival. Germline BRCA mutations are associated with worse PCa outcomes. BRCA carriers are currently treated with the same protocols used for non-carriers. We analyzed biochemical-progression free survival (bPFS) after conventional treatment for localized PCa in a cohort of BRCA patients (pts). Methods: In this retrospective case-control study, each BRCA carrier (9 BRCA1 and 34 BRCA2) treated with radical prostatectomy (RP) or external beam radiotherapy (RT) was matched with 3 non-carriers (NC) by age at diagnosis (±5 yrs), TNM stage, Gleason score, presenting PSA, local treatment , androgen-deprivation therapy (ADT) and year of treatment (±3 yrs). All NC were screened for BRCA1 and BRCA2 mutations. Biochemical failure was reviewed according to ASTRO and NCCN criteria. The Kaplan-Meier method and a multivariate Cox regression model adjusted by matching factors were employed. Results: 172 pts were included. Median follow-up was 76 months (ms). Median age at diagnosis was 58 yrs (43-75). Tumour stages were I 11%, IIA 19%, IIB 28%, III 28%, IV 14%. 80 pts received RT (18 BRCA2, 5 BRCA1, 57NC) and 85% also received ADT (70% for ≥6 months). 92 pts underwent RP (16 BRCA2, 4 BRCA1 and 72 NC), and 9% of them received ADT (<6months). Overall, median bPFS was 71ms. For those treated with RT, median bPFS was 65ms in NC vs 39ms in BRCA carriers (p=0.023). bPFS was not affected by ADT duration. Median bPFS after RP was 65ms in BRCA carriers. No difference was observed in 3yrs-bPFS between BRCA carriers and NC (73% vs 76%). The adjusted MVA confirmed the independent prognostic value of tumour stage (p=0.004) and BRCA status (p=0.032) for bPFS. Among BRCA carriers, the risk was greater when the analysis was limited to BRCA2 pts (p=0.013, HR 2.1,.95%CI 1.2-3.7). Conclusions: Our results suggest that BRCA carriers with PCa have worse local disease control than NC when treated with RT, regardless of ADT duration. No differences in bPFS were observed in pts treated with RP after >6 yrs median follow-up. These results may have implications for tailoring clinical management for these patients.