Cancer Center Network Breadth Not Linked to Lower MA Disenrollment Rates

Medicare Advantage (MA) offers beneficiaries a broader bandwidth of covered services, but researchers are concerned that narrow provider networks may limit access to specialized cancer care.¹

Research focused on network bandwidth, MA disenrollment, and beneficiaries with complex cancer cases is minimal, but a new study published in JAMA Network Open suggests there is no association between network breadth changes and employer-sponsored MA plan switching.¹ MA plans use tools like utilization management, health care facility network restrictions, and the Oncology Care Model—which was associated with lower spending for MA beneficiaries—to control costs.² These plans also offer other benefits like transport to care and meal delivery, for example. However, by excluding expensive, yet high-quality, cancer care centers from networks, researchers suggest it may be a strategy to deter enrollees with high costs, thus reducing overall health care costs.¹

Prior research suggests that one way to measure plan dissatisfaction is by enrollee disenrollment and found that those with high health care needs were more likely to disenroll from MA. Other research also found that beneficiaries with new cancer diagnoses were associated with exits from MA. But there was still limited data on the association between network breadth for cancer care facilities and changes in coverage for MA beneficiaries newly diagnosed with cancer.

The study authors used data from the Surveillance, Epidemiology, and End Results-Medicare-Linked database from 2019 to 2020. The analysis included beneficiaries newly diagnosed with lung, breast, leukemia, lymphoma, prostate, or colorectal cancers. The study cross-assessed diagnoses with the number of Commission on Cancer (COC)-associated facilities and National Cancer Institute-designated cancer centers located in each network-level service area.

Using this data, they compared narrow networks—those with less than 25% of facilities in the network’s geographic service area that were in-network—and non-narrow networks.

Network Breadth Varied Widely Across Medicare Advantage Plan Types

The study population included 24,444 MA beneficiaries diagnosed with cancer in 2019. There were 13,216 (54.1%) individuals in plans with narrow networks with a mean age of 72.2 years, and of them, 48.9% were male. Patient demographic data identified 18.9% of beneficiaries as Black, 14.9% as Hispanic, and 57.2% as White.

There were 11,228 beneficiaries in a non-narrow network with a mean age of 73.4 years. Of them, 50.2% were male. Patient demographic data identified 14.4% as Black, 12.0% as Hispanic, and 66.0% as White.

Beneficiaries in narrow networks were more likely to be younger, Black, and dual eligible for Medicare and Medicaid when compared with those in non-narrow networks (3191 beneficiaries [24.1%] vs 1844 beneficiaries [16.4%]).

Network breadth was also examined to determine whether an enrollee was in a non-employer or employer plan and if the plan charged a premium or not. Enrollees in non-employer plans that did not charge a premium were in the narrowest networks (mean network breadth, 25.3%; 95% CI, 25.0%–25.6%), while those in employer plans had the broadest networks (mean network breadth, 45.1%; 95% CI, 44.8%–45.5%).

Cancer Diagnosis Did Not Uniformly Drive Disenrollment From Medicare Advantage Plans

Although researchers did not find changes in network breadth to be associated with enrollee MA exits, the data did suggest that beneficiaries in non-employer plans were less likely to switch coverage when network breadth increased. Specifically, the study authors observed a 10-percentage-point increase in network breadth associated with a 4.5-percentage-point decrease in switching among premium non-employer plans. Whereas those in non-employer plans with 0 premium were more likely to switch when network breadth increased.

“Our results illustrate how network composition may be associated with different outcomes among beneficiaries depending on their pre-diagnosis MA enrollment options,” the study authors wrote.

The study was limited by a potentially unreliable data source, Ideon, which is known to have inaccuracies. The study may also not be generalizable to the MA beneficiary national population with cancer diagnoses.

“Our results indicate that network breadth may matter differentially depending on the type of enrollment, highlighting the need to ensure that all plans meet network adequacy requirements,” the study authors concluded.

References

1. Kothari EMA, Dusetzina SB, Graves JA, Stevenson DG, Keohane LM. Access to specialty cancer care and plan disenrollment among Medicare beneficiaries. JAMA Netw Open. 2026;9(6):e2618677. doi:10.1001/jamanetworkopen.2026.18677

2. Mullangi S, Ukert B, Devries A, et al. Association of participation in Medicare’s oncology care model with spending utilization, and quality outcomes among commercially insured Medicare Advantage members. J Clin Oncol.2025;43(2):133-142. doi:10.1200/JCO.24.00502