Racial disparities in cascade testing for cancer predisposition genes

We sought to determine whether there are racial disparities in cascade testing rates and whether providing testing at no-charge impacts rates in Black and White at-risk-relatives (ARR). Probands with a pathogenic/likely pathogenic germline variant in a cancer predisposition gene were identified up to one year before and up to one year after cascade testing became no-charge in 2017. Cascade testing rates were measured as the proportion of probands who had at least one ARR obtain genetic testing through one commercial laboratory. Rates were compared between self-reported Black and White probands using logistic regression. Interaction between race and cost (pre/post policy) was tested. Significantly fewer Black probands than White probands had at least one ARR undergo cascade genetic testing (11.9% versus 21.7%, OR 0.49, 95% CI 0.39–0.61, p < 0.0001). This was seen both before (OR 0.38, 95% CI 0.24–0.61, p < 0.001) and after (OR 0.53, 95% CI 0.41–0.68, p < 0.001) the no-charge testing policy.