Is Reflex Germline 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 reflex-tested for germline and tumour / variants. The value of germline 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 tumour 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 tumour testing for homologous recombination deficiency (HRD) using Myriad's myChoice® companion diagnostic. Seven-hundred-two patients successfully underwent both germline and tumour testing. Of these, 48 were diagnosed with non-mucinous high-grade EOC aged ≥80. In this age group, somatic pathogenic/likely pathogenic variants (PV/LPVs) were detected nine times more often than germline PV/LPVs. The only germline PV reported in a patient aged ≥80 was detected in germline and tumour DNA ( c.4478_4481del). No patient aged ≥80 had a germline PV/LPVs in a non- HRR gene. Thirty-eight percent of patients aged ≥80 had a tumour positive for HRD. Our data suggest that tumour and HRD testing is adequate for patients diagnosed with non-mucinous high-grade EOC aged ≥80, with germline testing reserved for women with a tumour PV/LPVs.