Race as an independent risk factor for breast cancer survival: breast cancer outcomes from the medical college of georgia tumor registry.

BACKGROUND: Causes of racial disparities in breast cancer survival remain unclear. This study assesses overall survival (OS) after diagnosis between black and white women and examines factors that might correlate with this disparity. PATIENTS AND METHODS: Data were obtained from the Medical College of Georgia Tumor Registry. Cases included those diagnosed between 1990 and 2005. We analyzed race, stage, age of diagnosis, and treatment received: chemotherapy, radiation, surgery, and hormonal therapy. A Cox proportional hazards model was used to determine differences in OS.
RESULTS: Compared with 670 white women, 489 black women were more likely to be younger, have later-stage disease at diagnosis, and were less likely to have received hormonal therapy. Both groups received similar rates of radiation, surgery, and chemotherapy. Black women had significantly poorer OS (adjusted hazard ratio, 1.35; 95% CI, 1.12-1.63). White women had a 5-year OS of 54% compared with 45% in black women (P = .0031). Having received radiation, surgery, or chemotherapy was not associated with OS. White women were more likely to have received hormonal therapy, which had a significant protective effect. However, a stratified analysis (between those who received hormonal therapy and those who did not) showed similar results, whereas black women experienced poorer OS in both strata.
CONCLUSION: Black women with breast cancer had a significantly poorer OS compared with white women. White women received more hormonal therapy, which had a protective effect. There were no differences in treatment received regarding radiation, surgery, or chemotherapy, and these treatments were not associated with OS. The reasons for racial disparities in breast cancer OS remain complex.