Association of Medicaid expansion with racial disparities in cancer stage at presentation

BACKGROUND: This study evaluates the independent association of Medicaid expansion on stage of presentation among patients of Black and White race with colorectal (CRC), breast, or non-small cell lung cancer (NSCLC). METHODS: A cohort study of patients with CRC, breast cancer, or NSCLC (2009–2017) in the National Cancer Database was performed. Difference-in-differences (DID) analysis was used to compare changes in tumor stage at diagnosis between Medicaid expansion (MES) and non-expansion states (non-MES) before and after expansion. Predictive margins were calculated by race, year, and insurance status to account for effect heterogeneity. Stage migration was determined by measuring the combined proportional increase in stage I and decrease in stage IV disease at diagnosis. RESULTS: Black patients gained less Medicaid coverage than White patients (6.0% vs 13.1%, p < 0.001) after expansion. Among Black and White patients, there was a shift towards increased early-stage diagnosis (DID 3.5% and 3.5%, respectively; p < 0.001) and decreased late-stage diagnosis (DID White: −3.5%; Black −2.5%; p < 0.001) in MES compared to non-MES following expansion. Overall stage migration was greater for White compared to Black patients with CRC (10.3% vs. 5.1%) and NSCLC (8.1% vs. 6.7%) after expansion. Stage migration effects in patients with breast cancer were similar by race (White 4.8% vs. Black 4.5%). CONCLUSION: An increased proportion of Black and White patients residing in Medicaid expansion states presented with earlier stage cancer following Medicaid expansion. However, because the proportion of Black patients is higher in non-expansion states, national racial disparities in cancer stage at presentation appear worse following Medicaid expansion.