Clinical outcomes of BRCA1/2 pathogenic variants in ovarian cancer cluster region in patients with primary peritoneal, epithelial ovarian, and fallopian tube cancer

An "ovarian cancer cluster region" (OCCR) has been reported in both BRCA1 and BRCA2. However, the clinical significance of the OCCR of BRCA1/2 has not yet been investigated.The medical records of 991 patients with epithelial ovarian, primary peritoneal, and fallopian tube cancer who underwent genetic testing for BRCA1 and/or BRCA2 from January 1, 2006, to August 31, 2019, were retrospectively reviewed. Sanger and next-generation sequencing analyses were used to test the BRCA1 and BRCA2 mutation status. Progression-free survival (PFS) and overall survival (OS) were compared according to the mutation location (OCCR vs. non-OCCR region). Survival outcomes were determined using Kaplan-Meier survival analysis.A total of 162 patients had BRCA1 pathogenic variants (PVs), and 76 had BRCA2 PVs. Patients with BRCA1 PV that in the OCCR region showed shorter PFS than those with BRCA1 PV outside the OCCR (22.6 months vs. 27.6 months, P = 0.038). In the platinum-sensitive subgroup of BRCA1, patients with BRCA1 PV in the OCCR region showed shorter PFS than those in the non-OCCR group (P = 0.0197). On the other hand, BRCA2 variants did not exhibit any particular trend (32.8 months vs. 27.9 months, P = 0.468). However, no significant differences were detected in OS between patients with BRCA1/2 PVs, regardless of the location of the variants.Patients with BRCA1 PV in the OCCR had shorter PFS than those outside the OCCR. This tendency was more pronounced in the platinum-sensitive subgroup. To our knowledge, this is the first study of BRCA1/2 mutations based on the OCCR.