A new abstract using a novel analysis by researchers at the American Cancer Society (ACS) shows Medicaid expansion under the Affordable Care Act was associated with an increase in Medicaid enrollment among patients 65 years old and older diagnosed with cancer. The results suggest spillover benefits of Medicaid expansion in supporting low-income elderly populations with cancer. The findings [were] presented at the annual American Society of Clinical Oncology (ASCO) Quality Care Symposium in San Francisco, September 27–28, 2024.


In the study, led by Kewei Sylvia Shi, associate scientist in health services research at the American Cancer Society, scientists identified patients 65 years old or older, newly diagnosed with cancer between 2010 and 2022, residing in areas with median income below 200% of the federal poverty level  from the National Cancer Database. Researchers applied a quasi-experimental design with difference-in-difference approach to compare the changes in the percentage of dual-eligible or Medicaid-only coverage post (vs. pre) Medicaid expansion in expansion vs. non-expansion states. Analyses were also stratified by key demographic characteristics.

Researchers identified 1,790,673 patients with cancer, with 971,164 patients from expansion states and 819,509 patients from non-expansion states. After adjusting for sociodemographic characteristics, the percentage of patients with dual or Medicaid-only coverage increased from 11.08 to 11.43 in expansion states and decreased from 9.21 to 8.09 in non-expansion states, resulting in a net increase of 1.27 percentage points associated with Medicaid expansion. Differences were more pronounced among patients diagnosed with stage III-IV cancers, racialized as non-Hispanic Black, residing in metropolitan areas, with two or more comorbidities, and treated in comprehensive or academic cancer centers.

Although not the target population of Medicaid expansion under the Affordable Care Act, researchers emphasize that elderly individuals may benefit from Medicaid expansion through “welcome mat” effects – the indirect increase in enrollment, particularly those who are low-income and eligible for both Medicaid and Medicare.

This news release was published by the American Cancer Society on September 23, 2024.