Socioeconomic status and breast carcinoma survival in four racial/ethnic groups: a population-based study

BACKGROUND: Although overall survival for invasive breast carcinoma remains high, black women experience poorer survival than whites. Less is known about the survival of Hispanics and Asians, who may share clinical and socioeconomic risk factors similar to blacks. To better understand racial/ethnic survival patterns, we investigated the effect of socioeconomic status (SES) and disease stage on racial/ethnic differences in breast carcinoma survival in a large population-based cohort. METHODS: Using data from the Surveillance, Epidemiology, and End Results program (SEER), we identified 10,414 white, 940 black, 1100 Hispanic, and 1180 Asian females diagnosed with breast carcinoma in the Greater San Francisco Bay Area between 1988 and 1992. We used the Kaplan-Meier method to generate survival rates and Cox proportional hazards regression to estimate the risk of death by race/ethnicity, after adjustment for clinical, demographic, and census-derived SES variables. RESULTS: The 10-year unadjusted survival rates were 81% for whites, 69% for blacks, 75% for Hispanics, and 79% for Asians. Adjusting for stage decreased the relative risk of mortality for blacks from 1.81 to 1.29; the stage-adjusted relative risk for Hispanics (1.11) and Asians (1.02) did not differ significantly from whites. Additional adjustment for age, tumor characteristics, and treatment factors did little to alter the relative risk in blacks; adding blue-collar status to the model further decreased the relative risks for blacks to 1.22. Residing in a blue-collar neighborhood was independently associated with a 1.16 increase in risk of death. CONCLUSIONS: After adjustment for multiple factors, blacks continue to have slight but significantly poorer survival after breast carcinoma compared with whites, whereas the survival of Hispanics and Asians did not differ from whites.