Association of Insurance Status and Racial Disparities With the Detection of Early-Stage Breast Cancer.

Importance: Compared with non-Hispanic white women, racial/ethnic minority women receive a diagnosis of breast cancer at a more advanced stage and have higher morbidity and mortality with breast cancer diagnosis. Access to care with adequate insurance may be associated with earlier diagnosis, expedited treatment, and improved prognosis. Objective: To examine the extent to which insurance is associated with access to timely breast cancer diagnosis and breast cancer stage differences among a large, diverse population of US patients with breast cancer. Design, Setting, and Participants: This retrospective, cross-sectional population-based study used data from the Surveillance, Epidemiology, and End Results Program on 177 075 women aged 40 to 64 years who received a diagnosis of stage I to III breast cancer between January 1, 2010, and December 31, 2016. Statistical analysis was performed from August 1, 2017, to October 1, 2019. Main Outcomes and Measures: The primary outcome was the risk of having a more advanced stage of breast cancer at diagnosis (ie, stage III vs stages I and II). Mediation analyses were conducted to determine associations of race/ethnicity and proportion of observed differences mediated by health insurance status with earlier stage of diagnosis. Results: A total of 177 075 women (mean [SD] age, 53.5 [6.8] years; 148 124 insured and 28 951 uninsured or receiving Medicaid) were included in the study. A higher proportion of women either receiving Medicaid or who were uninsured received a diagnosis of locally advanced breast cancer (stage III) compared with women with health insurance (20% vs 11%). In multivariable models, non-Hispanic black (odds ratio [OR], 1.46 [95% CI, 1.40-1.53]), American Indian or Alaskan Native (OR, 1.31 [95% CI, 1.07-1.61]) and Hispanic (OR, 1.35 [95% CI, 1.30-1.42]) women had higher odds of receiving a diagnosis of locally advanced disease (stage III) compared with non-Hispanic white women. When adjusting for health insurance and other socioeconomic factors, associations between race/ethnicity and risk of locally advanced breast cancer were attenuated (non-Hispanic black: OR, 1.29 [95% CI, 1.23-1.35]; American Indian or Alaskan Native: OR, 1.11 [95% CI, 0.91-1.35]; Hispanic: OR, 1.17 [95% CI, 1.12-1.22]). Nearly half (45%-47%) of racial differences in the risk of locally advanced disease were mediated by health insurance. Conclusions and Relevance: This study's findings suggest that nearly half of the observed racial/ethnic disparities in higher stage at breast cancer diagnosis are mediated by health insurance coverage.