Abstract
BACKGROUND: The cancer stage at diagnosis, treatment delays, and breast cancer mortality vary with insurance status. METHODS: Using the Missouri Cancer Registry, this analysis included 31,485 women diagnosed with invasive breast cancer from January 1, 2007, to December 31, 2015. Odds ratios (ORs) of a late-stage (stage III or IV) diagnosis and a treatment delay (>60 days after the diagnosis) were calculated with logistic regression. The hazard ratio (HR) of breast cancer mortality was calculated with Cox proportional hazards regression. Mediation analysis was used to quantify the individual contributions of each covariate to mortality. RESULTS: The OR of a late-stage diagnosis was higher for patients with Medicaid (OR, 1.72; 95% confidence interval [CI], 1.56-1.91) or no insurance (OR, 2.30; 95% CI, 1.91-2.78) in comparison with privately insured patients. Medicare (OR, 1.21; 95% CI, 1.10-1.37), Medicaid (OR, 1.60; 95% CI, 1.37-1.85), and uninsured patients (OR, 1.58; 95% CI, 1.18-2.12) had higher odds of a treatment delay. The HR of breast cancer-specific mortality was significantly increased in the groups with public insurance or no insurance and decreased after sequential adjustments for sociodemographic factors (HR, 2.39; 95% CI, 1.96-2.91), tumor characteristics (HR, 1.28; 95% CI, 1.05-1.56), and treatment (HR, 1.23; 95% CI, 1.01-1.50). Late-stage diagnoses accounted for 72.5% of breast cancer mortality in the uninsured. CONCLUSIONS: Compared with the privately insured, women with public or no insurance had a higher risk for advanced breast cancer, a >60-day treatment delay, and death from breast cancer. Particularly for the uninsured, Medicaid expansion and increased funding for education and screening programs could decrease breast cancer disparities.