The correlation between BRCA status and surgical cytoreduction in high-grade serous ovarian carcinoma.

Abstract

5543 Background: High grade serous ovarian cancers (HGSC) with BRCA mutation are biologically unique, with distinct molecular and clinical behaviour from sporadic cases. It is unclear if these biological differences translate to favorable outcomes at the time of primary cytoreductive surgery (PCS). The aim of this study is to compare the amount of residual disease following PCS in BRCA-mutated (BRCAm) and wildtype (BRCAwt) HGSC, and to assess whether BRCA status is an independent predictor of residual disease. Methods: We conducted a retrospective analysis of patients with HGSC with known germline and somatic BRCA mutation status, treated with PCS from 2000 to 2017. We compared the cytoreduction outcomes between the BRCAm and the BRCAwt cohorts and built a predictive model to assess whether BRCA status was associated with amount of residual disease at the time of PCS. Results: Of 355 women, 144 harbored germline or somatic BRCA mutations (41%) and 211 were BRCAwt (59%). BRCAm women tended to be younger (54 vs. 59; p < 0.001), but there were no differences between the two groups in stage, disease burden at presentation, surgical complexity score, length of surgery, or perioperative complications. The BRCAm group had a higher rate of complete cytoreduction to no residual disease (0mm) [75% vs. 54%], and a lower rate of optimal cytoreduction (1-9mm) [16% vs. 34%] or suboptimal cytoreduction (≥10mm) [9% vs. 12%] (p < 0.001). In our predictive model, after accounting for length of surgery, CA-125 level, stage, disease scores and surgical complexity scores, BRCAm status was predictive of complete cytoreduction to 0mm residual disease (OR 4.78; 95% CI 2.32-9.85; p < 0.001). Conclusions: BRCA 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.