Is reflex germline BRCA1/2 testing necessary in women diagnosed with non-mucinous high-grade epithelial ovarian cancer aged 80 years or older?

Women diagnosed with non-mucinous high-grade epithelial ovarian cancer (EOC) in England are often reflexed tested for germline and tumor BRCA1/2 variants. The value of germline BRCA1/2 testing in women diagnosed aged ≥80 is questionable. We performed an observational study of all women diagnosed with non-mucinous high-grade EOC who underwent germline and tumor BRCA1/2 testing by the North West of England Genomic Laboratory Hub. A subgroup of women also underwent germline testing using a panel of Homologous Recombination repair (HRR) genes and/or tumor testing for Homologous Recombination deficiency (HRD) using Myriad’s myChoice CDx. Seven-hundred-and-two patients successfully underwent both germline and tumor BRCA1/2 testing. Of these, 48 were diagnosed with non-mucinous high-grade EOC aged ≥80. In this age group, somatic BRCA1/2 likely pathogenic/pathogenic variants (LP/PVs) were detected nine times more often than germline BRCA1/2 LP/PVs (ratio 9:1). The only germline PV reported in a patient aged ≥80 was detected in germline and tumor DNA (BRCA2 c.4478_4481del). No patient aged ≥80 had a germline LP/PV in a non-BRCA1/2 HRR gene. Thirty-eight percent of patients aged ≥80 had a tumour positive for HRD. Our data suggests that tumor BRCA1/2 and HRD testing is adequate for patients diagnosed with non-mucinous high-grade EOC aged ≥80, with germline BRCA1/2 testing reserved for women with a tumor BRCA1/2 LP/PV.