Introduction/Background Between 10–15% of patients with epithelial ovarian cancer (EOC) carry a germline mutation in BRCA1/2. Different studies suggest that this population has a better prognosis. The purpose of our study is to analyse our BRCA1/2 germline mutated (gBRCA1/2m) population with EOC and to compare it with BRCA1/2 germline wild-type (gBRCA1/2wt) population.

Methodology Retrospective analysis in 158 patients with endometrioid or high-grade serous ovarian cancer with BRCA1/2 germline genetic study performed at our Hereditary Cancer Unit from February 2008 to April 2020. Patients with other histologies or pathogenic germline variants in other genes were excluded.

We described baseline characteristics and performed a comparative analysis between both cohorts at diagnosis and recurrence. Statistical analysis was performed with Wald tests, with STATA/IC 16.1.

Results Baseline characteristics are described in table 1. Median follow-up was 58 months. At diagnosis, gBRCA1/2m patients needed less neoadjuvant chemotherapy (24.4% vs. 50.4%, p=0.01). gBRCA1/2m patients had cytoreductive surgery (primary or interval) in a higher proportion (97.6% vs. 88%, p=0.07) and lower rate of residual disease after first-line treatment (9.8% vs 18.8%, p=0.18). The rate of relapse was lower in gBRCA 1/2m patients (48.8% vs 79.5%, p=0.001) and, platinum resistant or refractory (PR-R) relapse occurred in a lower percentage (5% vs 14%, p=0.26). gBRCA1/2m patients underwent secondary cytoreduction more frequently (45% vs 25.8%, p=0.11) and after second-line treatment presented residual disease in a lower proportion (45% vs 63.4%, p=0.27). The rate of second tumour progression was similar between both cohorts (90% vs 80.8% p=0.31), but among gBRCA 1/2m patients there were not any PR-R at that moment (0 vs 46.5% p=0.00).

Conclusion In our centre, EOC gBRCA1/2m patients underwent primary cytoreduction more frequently than gBRCAwt patients, and there was a trend toward a higher rate of surgery and lower rate of residual disease, both at diagnosis and at first relapse.

Disclosures No disclosures.