Abstract
BACKGROUND: Half of ovarian high-grade serous carcinomas (HGSC) have homologous recombination deficiency (HRD). However, HRD is not well characterized in Black individuals who experience worse survival after a diagnosis of HGSC. The objective of this study was to characterize ovarian HGSC HRD and examine its association with survival by self-reported race. METHODS: HRD features were identified using matched tumor-normal whole-exome and RNA sequencing in an HGSC cohort. We calculated age- and stage-adjusted HR and 95% confidence intervals (CI) for survival, comparing individuals with a feature to those without, separately by self-reported race. RESULTS: Any HRD was associated with a 32% reduced risk of death in Black individuals compared with a 62% reduction in White individuals (Black HR = 0.68; 95% CI, 0.43-1.09; White HR = 0.38; 95% CI, 0.14-1.04). More of the germline and somatic variants detected among Black individuals were unannotated or variants of uncertain significance (VUS; germline 65% vs. 45%; somatic 62% vs. 50%). Black individuals with germline unannotated/VUS were more likely to have tumors with HRD scarring and a first-degree family history of breast or ovarian cancer compared with those without (HRD scar 71.4% vs. 49.6%; family history 68.4% vs. 34.6%). CONCLUSIONS: HRD testing informs precision-based medicine approaches that improve outcomes, but a higher proportion of VUS among Black individuals may complicate referral for such care leading to worse outcomes for Black individuals. IMPACT: Our findings emphasize the importance of recruiting diverse individuals in genomics research and better characterizing VUS.