Racial Disparities in Family Variant Testing for Cancer Predisposition Genes.

Purpose: Despite the substantial clinical impact of genetic testing, racial disparities exist in the delivery of this service. Here, we partnered with a commercial laboratory (Invitae) to establish whether there are racial disparities in the uptake of family variant testing (FVT). We also investigated if providing FVT at no cost impacts rates of cascade testing in Black and White families. Methods: This is a retrospective analysis comparing rates of FVT in self-reporting Black probands to self-reporting White probands who underwent germline genetic testing for genes associated with hereditary cancer through Invitae. All Black and White patients found to have a pathogenic/likely pathogenic variant P/LPV) in a hereditary cancer syndrome gene were identified up to one year before and up to one year after FVT became no-charge in 1/2017. The proportion of probands with at least one at-risk family member who underwent FVT was compared between Black and White probands using logistic regression, including the interaction between covariates of cost and race. Results: Between 1/2016 and 1/2018, 8,530 Black and 87,846 White probands underwent genetic testing. Of these, 9.3% (n =791) Black probands and 11.4% (n=9,998) White probands had a P/LPV identified. The uptake of FVT, defined by percentage of positive probands with at least one family member undergoing testing, was significantly lower in Black participants compared to White participants (11.9% versus 21.7%, odds ratio 0.5, 95% CI 0.4-0.6, p<0.001). Period of testing before or after FVT was no-charge did not impact this difference (p=0.23 for the interaction). FVT rates were significantly lower in Black patients compared to White patients both before (8.1% versus 18.7%, OR 0.4, 95% CI 0.2-0.6, p<0.001) and after (13.6% versus 23.1%, OR 0.5, 95% CI 0.4-0.7, p<0.001) testing became no-charge. Conclusion: While FVT rates were low overall, they were significantly lower in Black families compared to White families. Cost of FVT did not have a significant impact on the racial disparity seen, suggesting additional barriers exist. Recognizing these disparities and determining the contributing factors are crucial to developing tailored interventions that would ultimately advance racial equity in cancer care. [ABSTRACT FROM AUTHOR]