Medicaid Expansion and Participation in Cancer Clinical Trials Among Patients Insured by Medicaid

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Investigators may have uncovered the impact of the 2014 and 2015 Medicaid expansion on cancer clinical trial participation, according to a recent study published by Unger et al in JAMA Oncology. The new findings suggested that Medicaid expansion under the Patient Protection and Affordable Care Act may have resulted in a 19% annual increase in Medicaid-insured patient participation in publicly funded cancer clinical trials.

“An individual’s type of insurance can be a strong indicator of their socioeconomic status, and … represents a social determinant of health,” explained lead study author Joseph Unger, PhD, Associate Professor in the Division of Public Health and a health services researcher at Fred Hutch Cancer Center. “We embarked on this analysis to better understand the extent to which this policy increased access to life-saving cancer clinical trials for [patients] insured through Medicaid,” he added.

Study Methods and Results

In this study, the investigators used the SWOG Cancer Research Network to analyze the data of 51,751 patients with cancer who participated in clinical trials from 1992 to 2020. The investigators then compared trends in Medicaid enrollment prior to the policy enactment to trends following its implementation.

In the years before the policy was enacted, they observed that enrollment in Medicaid corresponded largely with fluctuations in national economic conditions—especially patterns of unemployment. However, in the years after its implementation, the 19% annual increase in participation, compounded over time, resulted in 52% more patients with Medicaid insurance participating in cancer clinical trials than was projected had the policy not been implemented.

“This is an important finding … as it shows how socioeconomic conditions are strongly associated with who enrolls in clinical trials,” Dr. Unger highlighted. “This suggests that, going forward, it is important for researchers to more commonly consider the societal background of the participants when designing and conducting clinical trials and analyzing study data,” he emphasized.

In the years following enactment of the Affordable Care Act, the investigators found that increases in Medicaid enrollment were no longer closely associated with national economic events. They also noted that the impact of the policy change was more profound in states that implemented the Medicaid expansion in 2014 or 2015 compared with those that implemented expansion after 2015 or did not implement expansion at all.


“This study demonstrates that targeted policies not only can increase overall access to health care among [patients with] cancer, but also increase the accessibility of participating in a clinical trial,” Dr. Unger suggested. “Combined with a recent law requiring that state Medicaid programs cover the routine costs of participating in cancer clinical trials and new federal guidelines to design clinical trials to increase participation among underserved groups, we hope to see continued benefits in access to cancer clinical trials for [patients] insured by Medicaid,” he stressed.

The investigators hope to analyze whether their findings may extend to cancer clinical trials that are not publicly funded in future studies.

"It is reassuring as a researcher and a physician to see that efforts to increase insurance access can impact the accessibility of clinical trials and improve generalizability of the results,” underscored senior study author Dawn Hershman, MD, MS, FASCO, Interim Chief of the Division of Hematology Oncology at Columbia University Medical Center/NewYork-Presbyterian and Deputy Director of the Columbia University Herbert Irving Comprehensive Cancer Center. “These policy decisions make a difference, and we need to continue to advocate for them as a community,” she concluded.

Disclosure: The research in this study was funded by the National Institutes of Health, National Cancer Institute, National Clinical Trials Network, the Hope Foundation for Cancer Research, and the American Cancer Society. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.