Disparities in germline genetic testing results from a cohort of 493,515 black and white patients.

Abstract

10550 Background: When undergoing germline genetic testing (GGT), Black patients (pts) are more likely than non-Hispanic White (NHW) pts to receive uncertain results and less likely to receive definitive molecular diagnoses as the Black genome is less well-characterized. As GGT is increasingly pertinent to cancer care, it is important to explore the scope of these disparities. Methods: A retrospective cohort of clinician-reported Black and NHW pts who underwent GGT (43-84 genes) from 2015-2022 was evaluated. Frequencies of pathogenic/likely pathogenic (P/LP) and variant of uncertain significance (VUS) results were compared between Black and NHW pts. Rate and type of VUS reclassifications were also compared. Differences in proportions were determined using Chi-square test and significance was set at 0.05. Results: The cohort consisted of 493,515 pts (48,684 [10%] Black and 444,831 [90%] NHW). VUS results were significantly more frequent and P/LP results significantly less frequent for Black compared to NHW pts (46% vs. 32% and 9 vs.13%, respectively). This was also true for pts who reported a history of cancer, across all common hereditary cancer types (Table). Comparing Black to NHW pts, there were more unique instances of VUS reclassifications over time (13% of 13,629 vs. 9% of 53,195 unique VUS), including 12% vs. 8% downgraded to benign/likely benign and 0.9% vs. 1.3% upgraded to P/LP. Conclusions: Lower rates of actionable results limit risk-reducing interventions for Black pts and their families. However, VUS rates continue to decline, particularly in Black pts, as more individuals (of any race or ethnicity) are sequenced. Clinicians can be reassured that most (but not all) VUS that are reclassified are downgraded to benign. [Table: see text]