Introduction/Background BRCA1/2-driven ovarian cancers (OCs) compose a distinct group of OC, which is characterized by high sensitivity to platinum-based therapy. This study aimed to compare the disease outcomes in BRCA1/2 mutation carriers vs. non-carriers.

Methodology The analysis included 283 consecutive OC patients, who underwent optimal cytoreduction (size of residual tumor <1 cm (n=156) or complete tumor excision (n=127)) upon primary debulking surgery (PDS) (n=168) or after neoadjuvant chemotherapy (NACT) (n=115). 84 patients carried germ-line mutation in BRCA1 (n=78) or BRCA2 (n=6) genes, while 199 OCs were classified as sporadic cases.

Results Patients treated with NACT demonstrated inferior median disease-free interval (DFI) compared to women subjected to PDS followed by adjuvant therapy (7.9 months vs. 19.5 months, P<0.001). Interestingly, this difference remained clinically meaningful and statistically significant only for sporadic OC (5.1 months vs. 20.7 months, P<0.001), while BRCA1/2-driven carcinomas showed relatively similar DFI irrespectively of the sequence of the treatments (13.1 months vs. 16.7 months, P=0.11). The disease relapse was observed in 72/84 (86%) BRCA1/2-mutated patients and 165/199 (83%) women with sporadic cancer. 35/72 (49%) BRCA1/2-associated OCs relapsed by a single tumor lump, which was potentially amenable for radiological or surgical ablation; this estimate was significantly lower in sporadic cancer patients (52/165 (32%); P=0.01).

Conclusion BRCA1/2 status may contribute to the choice between PDS and NACT, therefore the turnaround time for BRCA1/2 testing may be important for proper treatment planning. BRCA1/2-driven OCs have more favorable pattern of relapses as compared to sporadic cases.

Disclosure This work has been supported by the Russian Science Foundation, grant 19-15-00168.