Introduction/Background Increasinf data supports fact that biological behavior of ovarian cancer in BRCA positive individuals differs from others. It is also generally assumed that germline BRCA mutations are found exclusively in patients with platinum sensitive disease.

The aim of this retrospective study was 1) to examine the prevalence of germline BRCA mutations in unselected ovarian cancer patients population, 2) to analyze whether biological behavior differs in BRCA+ and negative patients, and 3) to analyze possibility of platinum reinduction in platinum-resistant BRCA+ patients.

Methodology BRCA1/2 mutational analysis in peripheral blood samples from biobank by NGS and MLPA. Retrospective analysis of clinical data.

Results 364 unselected ovarian cancer patients in stages IIC-IV were included into study. Median follow-up of these patients was 37 months.

1. 44 of them harboured BRCA1 or BRCA2 mutation (12.1%). 29 of mutation carriers developed platinum sensitive recurrent disease (defined as PFS >6 months from each and last platinum-based chemotherapy), 15 of them developed platinum resistant disease.

2. there was no difference in PFS comparing BRCA positive patients to BRCA negative; there was a difference in PFS comparing BRCA negative vs. BRCA positive platinum sensitive vs. BRCA positive platinum resistant patients.

3. 7 of 15 BRCA positive platinum resistant patients were reinduced with platinum after one non-platinum chemotherapy line and they achived PFS median of 8 months (compared to others in this group with median PFS 4 months).

Conclusion

1. germline BRCA mutations are not exclusive for platinum sensitive ovarian cancer patients

2. we did not find difference in PFS for platinum sensitive BRCA positive and negative patients

3. platinum reinduction may be considered for BRCA positive platinum resistant ovarian cancer patients to prolong PFS

4. Even these data describes only small population, it opens several clinically important questions.

ConclusionSupported by Ministry of Health of the Czech Republic, grant nr. 17-32030.

Disclosure Nothing to disclose