Insurance status and racial disparities in detection of early-stage breast cancer.

Abstract

e18121 Background: Racial/ethnic minority women are diagnosed with later stage breast cancer. This study identifies the extent insurance can affect stage differences among a large, diverse population of breast cancer patients in the U.S. Methods: Retrospective, population-based study of women aged 40-64 years diagnosed with stages I-III breast cancer in the Surveillance, Epidemiology and End Results Program between 2010 and 2014. The primary outcome was risk of diagnosis with locally-advanced (stage III) versus early stage breast cancer (stages I-II). Causal mediation analyses were conducted to determine effects of race/ethnicity and proportion of observed differences mediated by health insurance status on earlier stage. Results: A total of 124,415 women (104,468 insured and 19,947 uninsured /Medicaid) were included. Among women with health insurance, a lower proportion was diagnosed with locally-advanced breast cancer compared to uninsured/Medicaid-covered women (11% versus 21%). In multivariable models, non-Hispanic Black (OR = 1.50, 95% CI 1.43-1.58), American Indian/Alaskan Native (OR = 1.38, 95% CI 1.11-1.72) and Hispanic (OR = 1.35, 95% CI 1.28-1.42) women had higher odds of being diagnosed with locally-advanced disease compared to non-Hispanic White women. When adjusting for health insurance and other socioeconomic factors, associations between race/ethnicity and risk of locally-advanced breast cancer were attenuated (non-Hispanic Black: OR = 1.30, 95% CI 1.23-1.37; American Indian/Alaskan Native: OR = 1.15, 95% CI 0.91-1.45; Hispanic: OR = 1.16, 95% CI 1.09-1.22). Approximately half (48% to 50%) of racial differences in risk of locally advanced disease were mediated by health insurance. Conclusions: We find that half of the observed racial/ethnic disparities in upstaging at diagnosis are mediated by health insurance coverage.