Racial disparities in genetic testing of breast cancer patients.

10591 Background: TNBC is disproportionately prevalent in African American (AA) populations and in women with BRCA-1 germline mutations. BRCA mutation carriers are candidates for targeted therapy with PARP-inhibitors, and testing results may influence risk-reducing surgery choice. Methods: We evaluated genetic testing patterns and outcomes for TNBC patients treated in the prospectively maintained databases of academic cancer programs in two metropolitan cities in the Northeast (New York City, NYC) and Midwest (Detroit, Det), 1998-2018. Median follow up was 3.73 years. Testing patterns were also analyzed by time, comparing pts diagnosed before versus after the mid-2013 Supreme Court ruling that expanded testing availability by banning gene patenting. Results: Of 810 pts, 600 were from NYC and 200 from Det; 202 were AA and 488 WA. Pts undergoing genetic testing were younger (median age 50 vs 62; p < 0.0001). Compared to WA, AA pts were less likely to undergo genetic testing overall (23.8% vs 42.0%; p < 0.0001) and within site (NYC: 25.6% vs 42.8%, p = 0.008; Det: 22.3% vs 38.6%, p = 0.025). No significant differences were seen in frequency of pathogenic BRCA mutations (AA-14.6%; WA-29.3%) or VUSs (AA-6.3%; WA- 4.9%); p = 0.20. Genetic testing disparities were reduced among pts diagnosed after mid-2013 (AA-31.4% vs WA-44.0%; p = 0.01) compared to pre-mid-2013 (AA-18.3% vs WA-40.7%; p < 0.0001). No differences were seen in local or distant recurrence free survival between patients with BRCA, BRCA variants of uncertain significance, non-BRCA mutations, and patients without genetic mutations (local recurrence p = 0.827; distant recurrence p = 0.574). This outcome equivalence was consistent when stratified by WA vs AA identity. Conclusions: Genetic testing has increased for TNBC pts following the mid-2013 Supreme Court ban on gene patenting, but race-associated disparities persist. Pts undergoing genetic testing are more likely to undergo risk-reducing mastectomy, but testing results do not affect survival outcomes, regardless of race. Addressing genetic testing disparities will become increasingly important as mutation-associated targeted therapies are identified through advances in precision medicine.