Growth in Medicare Advantage Enrollment and its Implications for Cancer Care Quality

/ABSTRACT There is a growing population of Medicare beneficiaries who are enrolled in Medicare Advantage (MA), an increasingly popular alternative to Traditional Medicare (TM) that administers Medicare benefits through private health plans. There are differences in benefit design between MA and TM, which create trade-offs in access to vs. affordability of cancer care. On the one hand, MA plans emphasize lower costs and provides supplemental benefits not covered in TM but employ utilization restrictions and selective networks to steer beneficiaries away from costly care. In particular, MA plans form selective provider networks that avoid larger, advanced cancer treatment facilities, such as NCI-designated cancer centers, that perform more complex and costly care. Such a risk-selection strategy can be used as a tool to avoid high-risk cancer patients. In comparison, TM imposes minimal restrictions on care but high cost-sharing, which may increase the financial burden of accessing care, especially for those without supplemental Medicare coverage. These trade-offs are consequential for patients with cancer, who experience pronounced care needs, but their impacts on cancer care delivery remain understudied. This early K99/R00 application proposes a comprehensive, mixed-methods study of cancer care quality in MA and TM, with a goal to establish Dr. Youngmin Kwon, PhD, as an expert investigator of MA policies and population-level cancer control in public insurance programs. Proposed training in MA encounter data, qualitative research methods, and clinical expertise in cancer care delivery will contribute to a successful execution of the study and support Dr Kwon’s transition to an independent investigator role. The K99 phase will leverage the Surveillance, Epidemiology, and End Results Program (SEER) cancer registries-linked Medicare data to assess acute care use (an outcome of poor care management) and specific cancer care process measures between aged MA and TM beneficiaries newly diagnosed with cancer (Aim 1). The aim will implement difference-in-differences and propensity-score weighted models to rigorously examine differences in acute care use and receipt of high-quality cancer care while controlling for predictors of plan selection. The R00 phase will focus on the role of selective MA networks (a critical feature of MA benefit design) and will encompass qualitative and quantitative components. Aim 2 will elicit the drivers of exclusion of NCI-designated cancer centers in MA networks through structured interviews of stakeholders at cancer centers and MA plans, which will identify challenges in ensuring adequate MA networks for cancer care delivery. This work will also inform Aim 3, which will formally quantify the impacts of MA networks on plan switching and cancer care quality by exploiting a significant drop in MA plans by health systems as an exogenous shock to plan networks. Together, these aims will provide novel evidence about the effects of MA coverage and plan networks on cancer care delivery, thereby informing proposals to reform the Medicare program and modifications to MA networks that can optimize cancer care delivery. Project Number: 1K99CA308260-01 | Fiscal Year: 2026 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: Youngmin Kwon | Institution: VANDERBILT UNIVERSITY MEDICAL CENTER, NASHVILLE, TN | Award Amount: $83,811 | Activity Code: K99 | Study Section: Special Emphasis Panel[ZRG1 CDPT-P (56)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11285877