Health Care Segregation, Physician Recommendation, and Racial Disparities in BRCA1/2 Testing Among Women With Breast Cancer

Purpose Racial disparities in BRCA1/2 testing have been documented, but causes of these disparities are poorly understood. The study objective was to investigate whether the distribution of black and white patients across cancer providers contributes to disparities in BRCA1/2 testing. Patients and Methods We conducted a population-based study of women in Pennsylvania and Florida who were 18 to 64 years old and diagnosed with invasive breast cancer between 2007 and 2009, linking cancer registry data, the American Medical Association Physician Masterfile, and patient and physician surveys. The study included 3,016 women (69% white, 31% black), 808 medical oncologists, and 732 surgeons. Results Black women were less likely to undergo BRCA1/2 testing than white women (odds ratio [OR], 0.40; 95% CI, 0.34 to 0.48; P < .001). This difference was attenuated but not eliminated by adjustment for mutation risk, clinical factors, sociodemographic characteristics, and attitudes about testing (OR, 0.66; 95% CI, 0.53 to 0.81; P < .001). The care of black and white women was highly segregated across surgeons and oncologists (index of dissimilarity 64.1 and 61.9, respectively), but adjusting for clustering within physician or physician characteristics did not change the size of the testing disparity. Black women were less likely to report that they had received physician recommendation for BRCA1/2 testing even after adjusting for mutation risk (OR, 0.66; 95% CI, 0.54 to 0.82; P,.001). Adjusting for physician recommendation further attenuated the testing disparity (OR, 0.76; 95% CI, 0.57 to 1.02; P = .06). Conclusion Although black and white patients with breast cancer tend to see different surgeons and oncologists, this distribution does not contribute to disparities in BRCA1/2 testing. Instead, residual racial differences in testing after accounting for patient and physician characteristics are largely attributable to differences in physician recommendations. Efforts to address these disparities should focus on ensuring equity in testing recommendations. (C) 2016 by American Society of Clinical Oncology