Impact of neighborhood and individual socioeconomic status on survival after breast cancer varies by race/ethnicity: The neighborhood and breast cancer study

Background: Research is limited on the independent and joint effects of individual- and neighborhood-level socioeconomic status (SES) on breast cancer survival across different racial/ethnic groups. Methods: We studied individual-level SES, measured by self-reported education, and a composite neighborhood SES (nSES) measure in females (1,068 non-Hispanic whites, 1,670 Hispanics, 993 African-Americans, and 674 Asian-Americans), ages 18 to 79 years and diagnosed 1995 to 2008, in the San Francisco Bay Area. We evaluated all-cause and breast cancer-specific survival using stage-stratified Cox proportional hazards models with cluster adjustment for census block groups. Results: In models adjusting for education and nSES, lower nSES was associated with worse all-cause survival among African-Americans (P_trend = 0.03), Hispanics (P_trend = 0.01), and Asian-Americans (P _trend = 0.01). Education was not associated with all-cause survival. For breast cancer-specific survival, lower nSES was associated with poorer survival only among Asian-Americans (P_trend = 0.01). When nSES and education were jointly considered, women with low education and low nSES had 1.4 to 2.7 times worse all-cause survival than women with high education and high nSES across all races/ethnicities. Among African-Americans and Asian- Americans, women with high education and low nSES had 1.6 to 1.9 times worse survival, respectively. For breast cancer-specific survival, joint associations were found only among Asian-Americans with worse survival for those with low nSES regardless of education. Conclusions: Both neighborhood and individual SES are associated with survival after breast cancer diagnosis, but these relationships vary by race/ethnicity. Impact: A better understanding of the relative contributions and interactions of SES with other factors will inform targeted interventions toward reducing long-standing disparities in breast cancer survival.