To compare the outcomes after intraperitoneal (IP) chemotherapy in patients with and without pathogenic BRCA mutations.

Patients with high grade ovarian cancer who were treated with adjuvant IP chemotherapy in the initial setting between 2005 and 2016 were identified. Outcomes were compared between patients with pathogenic mutations in BRCA (BRCA+) and those who tested negative or were unknown (BRCA-).

A total of 100 eligible patients were identified. The median follow-up was 47.0 months (range, 6.6-144.1 months). Of these 100 patients, 77 patients underwent BRCA testing; 25 patients (32%) were BRCA+ (23 germline, 2 somatic). No differences were noted between groups with respect to number of IP cycles, stage, or residual disease after surgery. The median progression-free survival (PFS) was longer in the BRCA+ group; median PFS was not reached in the BRCA+ group compared to 17.3 months in the BRCA- group (HR = 0.38; 95% CI 0.20-0.73, P = 0.003). Median overall survival (OS) was longer in the BRCA+ group at 110.4 months versus 67.1 months (HR = 0.28, 95% CI 0.11-0.73, P = 0.009).

Pathogenic BRCA mutations are more common than expected in optimally resected ovarian cancer patients selected for IP therapy. IP therapy was associated with a dramatic improvement in PFS and OS in BRCA+ patients compared with BRCA- patients. This improvement is greater than has been reported for BRCA+ patients with IV chemotherapy. The magnitude of this benefit suggests that patients with pathogenic mutations in BRCA may benefit from IP therapy.