Primary tumor size, not race, determines outcomes in women with hormone-responsive breast cancer

We sought to determine if there was a difference in outcomes in African-American compared with Caucasian women with hormone-responsive breast cancer, and whether this was related to race or other tumor and treatment variables.

We included 1,205 patients with hormone-responsive breast cancer were identified in the Kentucky Cancer Registry (1996-2007). The effect of race on survival was evaluated using Kaplan-Meier and Cox regression methodologies.

In this cohort, 76.9% were Caucasian and 21.7% were African American. Compared with Caucasians, African-American women were older (57 vs 55 years; P = .032) and more likely to have larger tumors (19 vs 17 mm; P = .009). No significant racial differences in grade, operative, or systemic treatment were noted. Univariate analysis found no significant differences in disease-specific overall survival (DSS) or disease-free survival (DFS) between Caucasians and African Americans (5-year actuarial DSS, 93.6% vs 90.7%, respectively; P = .205; 5-year actuarial DFS, 91.5% vs 90.4%, respectively; P = .829). On multivariate analysis, only tumor size remained an independent predictor of DSS (odds ratio [OR], 1.021; 95% confidence interval [CI], 1.013-1.028; P < .001). Controlling for age, tumor size, and insurance status, race did not influence DSS or DFS (P = .913 and P = .857).

African Americans present with larger tumors than Caucasians; treatment is similar. Tumor size, not race, affects disease-specific outcomes in patients with breast cancer.