Retrospective cohort study of the association of Medicaid expansion with overall mortality among women with breast cancer

Medicaid expansion under the Patient Protection and Affordable Care Act was designed to approve access to care and reduce health disparities. Its association with overall mortality in breast cancer patients and related disparities is not yet clear. A retrospective cohort study using a National Cancer Database cohort of 1,595,845 women aged 40 to 64 years with a diagnosis of breast cancer from 2006 to 2021, enrolled women living in expansion states before 2014 (57.8%) and in nonexpansion states (42.2%). Living in expansion states was associated with lower overall mortality (HR 0.95; p<0.001). Lower mortality was observed across disease stages, race and ethnicity, neighborhood income, and treatment strata, with the largest relative gains among Hispanic women and with smaller gains among non-Hispanic Black women and residents of low-income areas. The authors conclude that these findings suggest that Medicaid expansion was associated with improved survival among women with breast cancer, although the benefits were not equitably distributed.