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.