Health insurance and neighborhood poverty as mediators of racial disparities in advanced disease stage at diagnosis and nonreceipt of surgery for women with breast cancer

BACKGROUND: In our recent study, advanced disease stage and nonreceipt of surgery were the most important mediators of the racial disparity in breast cancer survival. The purpose of this study was to quantify the racial disparity in these two intermediate outcomes and investigate mediation by the more proximal mediators of insurance status and neighborhood poverty. METHODS: This was a cross‐sectional study of non‐Hispanic Black and non‐Hispanic White women diagnosed with first primary invasive breast cancer in Florida between 2004 and 2015. Log‐binomial regression was used to obtain prevalence ratios (PR) with 95% confidence intervals (CIs). Multiple mediation analysis was used to assess the role of having Medicaid/being uninsured and living in high‐poverty neighborhoods on the race effect. RESULTS: There were 101,872 women in the study (87.0% White, 13.0% Black). Black women were 55% more likely to be diagnosed with advanced disease stage at diagnosis (PR, 1.55; 95% CI, 1.50–1.60) and nearly twofold more likely to not receive surgery (PR, 1.97; 95% CI, 1.90–2.04). Insurance status and neighborhood poverty explained 17.6% and 5.3% of the racial disparity in advanced disease stage at diagnosis, respectively; 64.3% remained unexplained. For nonreceipt of surgery, insurance status explained 6.8% while neighborhood poverty explained 3.2%; 52.1% was unexplained. CONCLUSIONS: Insurance status and neighborhood poverty were significant mediators of the racial disparity in advanced disease stage at diagnosis with a smaller impact on nonreceipt of surgery. However, interventions designed to improve breast cancer screening and receipt of high‐quality cancer treatment must address additional barriers for Black women with breast cancer.