Black/white differences in treatment and survival among women with stage IIIB–IV breast cancer at diagnosis: a US population-based study

Introduction Non-Hispanic black (NHB) women with breast cancer have poorer survival than non-Hispanic white (NHW) women. Although NHB women are more often diagnosed at later stages, it is less established whether racial disparities exist among women diagnosed with late-stage breast cancer, particularly when care is provided in the community setting. Methods Treatment and survival were examined by race/ethnicity among women diagnosed in 2012 with stage IIIB–IV breast cancer using the National Cancer Institute’s population-based Patterns of Care Study. Medical records were re-abstracted and treating physicians were contacted to verify therapy. Vital status was available through 2014. Results A total of 533 women with stage IIIB–C and 625 with stage IV tumors were included; NHW women comprised about 70% of each group. Among women with stage IIIB–C disease, racial/ethnicity variations in systemic treatment were not observed but there was a borderline association indicating worse all-cause mortality among NHB women (hazard ratio 1.52; 95% confidence interval (CI) 0.96–2.41). In contrast, among women with stage IV disease, borderline associations indicating NHB women were more likely to receive chemotherapy (OR 1.44, 95% CI 0.90–2.30) and, among those with hormone receptor-positive tumors, less likely to receive endocrine therapy (OR 0.60, 95% CI 0.35–1.04). All-cause mortality did not vary by race/ethnicity for stage IV disease (hazard ratio 0.92; 95% CI 0.68–1.25). Conclusions More research is needed to identify additional factors associated with the potential survival disparities among women with stage IIIB–C disease and potential treatment disparities among women with stage IV disease.