The Effect of Risk-Reducing Salpingo-Oophorectomy on Breast Cancer Incidence and Histopathological Features in Women with a BRCA1 or BRCA2 Germline Pathogenic Variant

Background: Risk-reducing salpingo-oophorectomy (RRSO) is advised for female BRCA1/2 germline pathogenic variant (GPV) carriers to reduce tubal/ovarian cancer risk. RRSO may also affect breast cancer (BC) incidence. The aim was to investigate the effect of RRSO on BC incidence and histopathological features in female BRCA1/2 GPV carriers. Methods: Prospectively collected clinical data from BRCA1/2 GPV carriers in our hospital-based data/biobank were linked to the Dutch Nationwide Pathology Databank (PALGA) in January 2022. Multivariable Cox-proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (95% CIs), where the pre-RRSO group was considered the reference group and the primary endpoint was the first primary BC. Histopathological features of BCs pre- and post-RRSO were compared using descriptive statistics. Results: In 1312 women, 164 incident primary BCs were observed. RRSO did not decrease BC risk for BRCA1 GPV (HR: 1.48, 95% CI: 0.91–2.39) or BRCA2 GPV (HR: 0.95, 95% CI: 0.43–2.07) carriers. BCs tended to be smaller post-RRSO (median: 12 mm) than pre-RRSO (15 mm, p: 0.08). There were no statistically significant differences in histopathological features. Conclusions: RRSO did not decrease BC risk or affect BC features in BRCA1/2 GPV in this study, although BCs diagnosed post-RRSO tended to be smaller.