Robert Brophy’s white blood cell count has been low for nearly two years — a condition he describes as “kind of like a pre-leukemia.” Last April, his bladder quit working without warning. He needs ongoing specialist care, and he was getting it at Moffitt Cancer Center in Tampa, one of the top cancer hospitals in the US.

Then his insurance changed. Then it changed again.

Brophy first lost in-network access to Moffitt when Aetna dropped the cancer center from its Medicare Advantage network in December 2025. He switched to Humana. This month brought another notification: Humana will drop Moffitt from its Medicare Advantage plans effective July 1.

“The insurance companies have all the power and the money,” Brophy told FOX 13 Tampa.

He is not alone. A growing number of older Americans are discovering that the Medicare Advantage plan they chose no longer covers the hospital treating their cancer. The reasons have nothing to do with the quality of care.

A Contract Dispute With Human Costs

Moffitt’s position is blunt: the insurers initiated the separations. Aetna terminated its agreement “for business reasons that are unrelated to the quality of care provided by Moffitt,” the center stated. The language about Humana was nearly identical.

Aetna said it was “only one of a few Medicare Advantage plans that had Moffitt Cancer Center participating” and needed to “offer competitive benefits that seniors deserve.” Humana said it remained “deeply committed to supporting our members’ health and well-being.”

Neither addressed what happens to patients mid-treatment. Aetna noted that affected patients can request “Transition of Care coverage” — a temporary extension of in-network benefits, pending approval. After that, patients face higher out-of-pocket costs or the prospect of switching cancer centers.

Moffitt is not isolated. According to The Care Partner Project, a patient advocacy organization, at least a dozen major health systems have dropped or limited Medicare Advantage plans since 2024. The list includes Mayo Clinic, Johns Hopkins Medicine, and Scripps Health. Brookings Health System in South Dakota dropped all Medicare Advantage plans.

The Prior Authorization Machine

Why are hospitals walking away? Administrative burden.

Medicare Advantage insurers required providers to submit nearly 53 million prior authorization requests in 2024, according to KFF — 84 times the number under traditional Medicare. These authorizations cover chemotherapy, radiation, imaging, and inpatient stays: standard cancer care.

Insurers denied 4.1 million requests, a 7.7% denial rate. But when patients and providers appealed, they won 80.7% of the time — a rate above 80% for years running. If four in five denials are overturned on appeal, what is the process actually accomplishing?

Breastcancer.org reported that prior authorization requirements were “a major reason some cancer centers and hospitals recently stopped accepting” Medicare Advantage. The process delays treatment and shifts decisions from doctors to insurance adjusters.

Networks That Exclude

The network squeeze hits cancer patients with particular force. KFF found that one in five Medicare Advantage plans excludes academic medical centers. In regions with a top-tier cancer center, two in five plans leave it out entirely.

This is partly by design. Specialty cancer centers command higher reimbursement because their care is more complex. Insurers competing on premiums have a clear incentive to steer patients toward cheaper community hospitals. The clinical gap can be real: top centers offer clinical trials, tumor boards, and rare-case specialists that community hospitals cannot match.

The result is a structural trap. Original Medicare is accepted by virtually all hospitals and doctors. Medicare Advantage offers lower premiums and perks like dental and vision, but narrower networks and tighter restrictions. A 2023 study cited by Breastcancer.org found that Medicare Advantage enrollees with a cancer history were more likely to report financial strain than those on original Medicare.

Switching back is not simple. In most states, Medigap supplemental plans — which cover cost gaps in original Medicare — can deny coverage or charge higher premiums for pre-existing conditions.

No Voice at the Table

The political debate around Medicare Advantage centers on whether private insurers are overpaid. For patients in active treatment, the question is more immediate: will their oncologist still be covered next month?

Brophy now faces his third insurance search in two years. He called his Moffitt doctors and staff “great” and said “everybody has just been fantastic.” His access to them keeps depending on contract negotiations where he has no voice — and where terms change annually, regardless of whether his treatment is complete.

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