Objectives The aim of this study is to compare the amount of residual disease following primary cytoreductive surgery (PCS) in BRCA-mutated (BRCAm) and wildtype (BRCAwt) high-grade serous ovarian cancer (HGSC), and to assess whether BRCA status is an independent predictor of residual disease.

Methods We conducted a retrospective analysis of patients with stage III/IV HGSC with known germline and somatic BRCA status, treated with PCS from 2000 to 2017. We compared the cytoreduction outcomes and built a predictive model to assess whether BRCA status was associated with amount of residual disease at the time of PCS.

Results of 303 women, 120 harbored germline or somatic BRCA mutations (40%) and 183 were BRCAwt (60%). BRCAm women tended to be younger (54 vs. 59; p<0.001), but there were no differences between the two groups in disease burden at presentation, surgical complexity, length of surgery, or perioperative complications. The BRCAm group had a higher rate of complete cytoreduction to no residual disease (0mm) [72% vs. 48%], and a lower rate of optimal cytoreduction (1–9mm) [19% vs. 38%] or suboptimal cytoreduction (≥10mm) [10% vs. 14%] (p<0.001). After accounting for length of surgery, CA-125 level, disease scores and surgical complexity scores, BRCAm status was predictive of complete cytoreduction to 0mm residual disease (OR 5.2; 95% CI 2.44–11.1; p<0.001).

Conclusions BRCAm status is predictive of complete cytoreduction at time of PCS in HGSC. Timely availability of BRCA testing is paramount as it may aid in the therapeutic decision making between PCS or neoadjuvant chemotherapy in women with newly diagnosed HGSC.