Prior studies have shown that over a span of 20 years (1990-2009), breast cancer death rates in the U.S. have not significantly declined for American Indians (AIs) in comparison to the White population. Health insurance coverage contributes independently and positively to the health of individuals through the receipt of adequate preventive services and care for diseases such as breast cancer. To this end, the 2010 Medicaid Expansion as part of the Affordable Care Act (ACA) has extended the health insurance coverage eligibility to adults with incomes up to 133 percent of the federal poverty level. In this study, we examined whether Medicaid expansion resulted in the improvement of breast cancer management and prognosis for AIs relative to the White population. Methods: We abstracted information from the National Cancer Data Base (NCDB) for AI and White breast cancer patients diagnosed between the years 2004-2016 who lived in states that expanded Medicaid in January 2014, and those that did not expand Medicaid. Data on age, race, stage at diagnosis, insurance status, definitive treatment initiation within 30 days of diagnosis, and 3-year mortality was analyzed. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multiple logistic regression to determine the impact of race (White vs. AI), Medicaid expansion status, and pre- vs. post-expansion periods on breast cancer management and prognosis. All p-values are two-sided. Analyses were performed using SPSS software V25. Results: There were 1,465,103 newly diagnosed White and AI breast cancers between the years 2004-2016; 99.7% were Whites and 0.3% were AIs. Of these, 46.9% resided in states that expanded Medicaid in January 2014 and 53.1% in states that did not expand Medicaid; 73.8% were diagnosed in the pre-expansion period (January 2004-December 2013) and 26.2% were diagnosed in the post-expansion period (January 2014-December 2016). There was an increase in the proportion of early stage (0, 1) breast cancer diagnosis in the period 2014-2016 as compared to the period 2004-2013 (OR=1.434, 95% CI:1.159- 1.775; p = 0.001), and this increase was significantly greater for AIs than for Whites (6% vs 3%; p=0.027) in both expansion and non-expansion states. An independent chi-square analysis of AIs found that there was a significant increase of the early stage diagnosis in the expansion states during the post-expansion period (p=0.001). The proportion of uninsured declined in the period 2014-2016 as compared to the period prior (OR=0.331, 95% CI: 0.129- 0.850; p=0.022), more so in the expansion states (decrease from 1.4% to 0.8%), vs. non expansion states (decrease from 2.3% to 2.2%) (p=0.019); no difference in decline was found between Whites and AIs. The probability of getting first definitive treatment within 30 days of diagnosis declined more in states without Medicaid expansion (decrease from 54% to 43%) than in states with Medicaid expansion (decrease from 50% to 43%) (p=0.028) for both AIs and Whites; and the decline was more in Whites (decrease from 55% to 44%) than in AIs (decrease from 49% to 42%) from pre-expansion period to post-expansion period (p=0.018). The 3-year mortality rates did not show any significant relationship to race, expansion status, or the pre- or post-expansion periods. Conclusion: In patients newly diagnosed with breast cancer, the proportion of uninsured declined significantly with Medicaid expansion and the proportion of patients who received first definitive treatment within 30 days of diagnosis decreased significantly less in AIs and in states that expanded Medicaid under the Affordable Care Act. Medicaid expansion increased early breast cancer diagnosis in AIs; this effect was not seen in non-expansion states. Medicaid expansion did not affect 3-year mortality rate.

Citation Format: Anu G Gaba, Li Cao, Rebecca Renfrew, Kristi A Egland, DeAnn L Witte, Janet Wernisch, Ross Crosby. Did Medicaid expansion under the Affordable Care Act narrow the gap between American Indians and Whites on breast cancer management and prognosis? [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SS1-08.