Breast Cancer Treatment Following Health Reform: Evidence From Massachusetts.

There are well-documented differences in breast cancer treatment by insurance status. Insurance expansions provide a context to assess the relationship between insurance and patterns of breast cancer care. We examine the association of Massachusetts health reform with use of breast conserving surgery, reconstruction, and adjuvant radiation using data from the Massachusetts Cancer Registry and Surveillance Epidemiology and End Results registries for 2001-2013 and a difference-in-differences approach. We observe statistically significant increases in breast conserving surgery among nonelderly women in Massachusetts relative to trends in states and age groups not affected by health reform. We also observe relative increases in reconstruction and adjuvant radiation, though trends in these outcomes were not the same across states prior to reform, limiting our ability to draw conclusions about the relationship between reform and these outcomes. Our results suggest that health reform was associated with some improvements in breast cancer treatment.