Medicaid Expansion Linked to Lower Breast Cancer Deaths, but Disparities Persist

Medicaid expansion under the Affordable Care Act (ACA) was associated with significantly lower mortality in women with breast cancer, according to a study of more than 1.5 million participants.¹ This lower mortality was largely observed across race and ethnicity, neighborhood income, disease stage, and treatment strata. However, benefits were not distributed equitably, indicating pervasive underlying disparities.

Published in JAMA Network Open, the study found that women with breast cancer living in Medicaid expansion states had a 4.8% lower risk of death compared with those in nonexpansion states. Researchers estimated this translates to roughly 1400 deaths averted for every 100,000 patients with cancer who gained coverage over 5 years.

Researchers analyzed data from the National Cancer Database on women aged 40 to 64 years who were diagnosed with breast cancer between 2006 and 2021. They used a difference-in-differences statistical approach to compare outcomes before and after the 2014 ACA Medicaid expansion rollout, comparing states that expanded Medicaid with those that did not. Women older than 64 years were excluded to avoid overlap with Medicare eligibility.

Hispanic women saw the largest gains, with a 19% reduction in mortality hazard in expansion states. Non-Hispanic Black women saw a more modest improvement of 4.3%, and non-Hispanic White women saw a 3.4% reduction. Crucially, when researchers looked at absolute 5-year survival figures, the benefit for non-Hispanic Black women was not statistically significant—a finding that points to deep, persistent inequities that expanded insurance coverage alone has not resolved.

“Insurance expansion is associated with improved outcomes but must be paired with targeted efforts to address persistent disparities,” the authors wrote.

The survival benefits were most pronounced in patients with the most advanced disease. Women with stage IV metastatic breast cancer in expansion states saw their mortality hazard fall by nearly 14%, compared with just 3% for patients with stage I disease. Those who received immunotherapy in expansion states experienced the largest difference of any treatment subgroup examined, with a striking 24% reduction in mortality hazard.

However, a surprising finding of the study was that women living in the lowest-income neighborhoods in expansion states actually fared worse after expansion. The data showed a 4.8% increase in mortality hazard compared with their counterparts in nonexpansion states. Women in middle- and higher-income neighborhoods, by contrast, saw reductions of roughly 9% to 11%.

This pattern likely reflects structural barriers that go beyond insurance coverage, including limited access to quality oncology services, transportation challenges, and other social determinants of health that disproportionately affect the poorest patients.²

The study findings suggest that the improved survival associated with Medicaid expansion may have been due to pathways such as timely detection, treatment initiation, and reducing delays in care.¹ Unlike previous research, the authors found that this significantly lower mortality existed even after accounting for disease stage and treatment. Therefore, the expansion was associated with improved survival due to early detection, treatment access, care continuity, and overall outcomes.

The findings add to a growing body of evidence that expanding public insurance coverage saves lives across disease stages and population characteristics even after controlling for factors such as comorbidity. However, the researchers caution that coverage is not enough on its own. The persistence of racial disparities, particularly for Black women who already face higher breast cancer mortality rates despite lower incidence, suggests that systemic barriers to timely diagnosis and high-quality treatment remain entrenched.

“Policies that pair coverage expansion with targeted efforts to improve timely diagnosis, treatment access, and adherence may be needed to close these gaps,” the authors concluded.

References

1. Akinyemi O, Oyebanji O, Fasokun M, et al. Medicaid expansion and overall mortality among women with breast cancer. JAMA Netw Open. 2026;9(1):e2554512. doi:10.1001/jamanetworkopen.2025.54512

2. Wilkerson AD, Gentle CK, Ortega C, Al-Hilli Z. Disparities in breast cancer care-how factors related to prevention, diagnosis, and treatment drive inequity. Healthcare (Basel). 2024;12(4):462. doi:10.3390/healthcare12040462