BRCA1/2 Carriers With Breast-Ovarian Double Primary Cancers Versus Ovarian Cancer Alone: Mutation Profiles and Survival Outcomes.

BRCA1/2

Location of germline BRCA1 and BRCA2 variants (outside or within the ovarian cancer cluster region, BRCA2 DNA-binding domain) associated with breast-ovarian double primary cancers

Germline BRCA1/2 pathogenic variants increase breast and ovarian cancer risk, but whether their characteristics predispose to breast-ovarian double primary cancers, and whether such double cancers affect outcomes in the PARP inhibitor era, remained unclear. This retrospective analysis in China (2015-2025) compared 114 patients with double primary cancers with 296 patients with ovarian cancer only, all carrying a germline BRCA1/2 variant and high-grade serous ovarian cancer. In the double cancer group, variants were more often located outside the ovarian cancer cluster region (BRCA1: 63.1% versus 48.9%; BRCA2: 80.0% versus 56.2%), and BRCA2 DNA-binding domain variants were enriched (33.3% versus 17.8%). Both groups benefited from first-line PARP inhibitor maintenance, with no significant difference in progression-free or overall survival.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

Variant location appears to influence susceptibility to double cancers, which could nuance the counselling given to carriers of variants outside the ovarian cancer cluster region. The cohort includes only patients already affected by high-grade serous ovarian cancer: it cannot estimate breast cancer risk in carriers in general. The absence of a survival difference is reassuring, but the authors themselves call for validation in larger, prospectively followed populations.

Analysis by Dr Thibaut Benquey