About 1,000 Medicare Advantage members enrolled in Mass General Brigham Health Plan are getting a defined window to keep receiving care at Dana-Farber Cancer Institute before that access ends. The health plan confirmed it will drop Dana-Farber from its Medicare Advantage network starting October 1, pointing to financial pressure it says is affecting Medicare Advantage plans nationwide. For members currently in treatment, what matters is a specific, time-limited mechanic: a 90-day transition period, not open-ended coverage, and members who take no action before that window closes lose in-network access to their Dana-Farber providers.
Mass General Brigham Health Plan Confirms the Dana-Farber Cutoff Number
Mass General Brigham (MGB) Health Plan disclosed the figure on September 9, 2026: about 1,000 of its Medicare Advantage members received services from Dana-Farber providers in the past year, the population directly affected by the October 1 network change. Jennifer St. Thomas, MGB Health Plan’s senior vice president of commercial and Medicare markets, said the decision reflects “the challenging environment that is impacting Medicare Advantage plans nationwide,” and said the plan is “working closely with Dana-Farber to support impacted members with care planning, dedicated assistance and clear guidance throughout the transition.”
MGB Health Plan operates and makes network decisions “separately, independently and without influence from” the broader Mass General Brigham health system, according to a statement the system shared with Becker’s Payer Issues. The change is limited to Medicare Advantage: MGB Health Plan’s commercial and MassHealth members keep their access to Dana-Farber providers.
Free retirement updates: One number can cost or save hundreds a month in retirement. The free Retirement Shield newsletter surfaces the ones worth knowing. Sign up free.
What the 90-Day Window After October 1 Actually Covers
The 90 days run from October 1 into roughly the end of December and let an affected member keep seeing Dana-Farber providers as an in-network benefit long enough to complete or transition an active course of treatment, according to MGB Health Plan. It is a plan-created accommodation, not a renewal of the underlying network contract: once the window closes, Dana-Farber providers revert to out-of-network status for any member still enrolled in an MGB Health Plan Medicare Advantage product. A Dana-Farber spokesperson told Becker’s that continuity of care is the cancer center’s “primary concern,” said the institute is “contacting all affected patients to discuss their options,” and said the cancer center would work to “mitigate the impact of MGBHP’s decision.” Neither organization has published a public list of which specific services qualify for the 90-day period, so individual outreach, rather than a general notice, is the channel both say they are using.
The Federal Notice Rules Behind Every Medicare Advantage Network Cut
Federal regulation sets the floor for how Medicare Advantage members are warned about a change like this one, but it governs the warning, not a guaranteed length of continued coverage. Under 42 CFR 422.111(e), a Medicare Advantage organization must notify enrollees before a contracted provider’s termination takes effect: at least 45 calendar days ahead of the date for a primary care or behavioral health provider, and at least 30 calendar days ahead for other specialty types, sent to enrollees currently assigned to that provider or who have used the provider recently. The notice must identify in-network alternatives and the plan’s enrollment options. Those requirements control timing and content of the warning; they do not, on their own, create a fixed number of additional days of in-network coverage after a provider leaves a network. That extra runway is what MGB Health Plan is layering on top, in the form of its own 90-day transition.
A Separate CMS 90-Day Rule Applies Only to Members Who Switch Plans
CMS does enforce a distinct, nationally mandated 90-day rule, but it answers a different question than the Dana-Farber network change does. Under the Contract Year 2024 Medicare Advantage and Part D final rule, coordinated care plans must provide a minimum 90-day transition period when an enrollee moves into a new Medicare Advantage plan while already undergoing an active course of treatment, and during that window the new plan cannot require prior authorization for that treatment. That protection is triggered by a person changing plans, not by an existing plan dropping one health system from its network while the member stays put. MGB Health Plan’s Dana-Farber accommodation is the latter case: a plan-level continuity-of-care period for members who are not changing Medicare Advantage plans, which is why the two 90-day figures, though identical in length, rest on different rules.
What Day 91 Means for Members Who Haven’t Transitioned Care
A member who reaches the end of the 90-day window still tied to Dana-Farber will find those providers billed as out-of-network, which under most Medicare Advantage cost-sharing structures means substantially higher out-of-pocket costs, or no coverage at all for non-emergency visits, depending on the specific plan’s out-of-network benefit. Members retain the standard tools available to any Medicare Advantage enrollee on the standard calendar: the Medicare Advantage Open Enrollment Period, which runs January 1 through March 31 and allows one switch to a different Medicare Advantage plan or back to Original Medicare, and the fall Annual Enrollment Period, October 15 through December 7, for coverage that starts the following January 1. Whether either window arrives in time to preserve uninterrupted Dana-Farber access depends on an individual member’s treatment schedule, which is the specific reason both MGB Health Plan and Dana-Farber describe their outreach as direct, patient-by-patient contact rather than a single public notice.
This article was produced with the assistance of AI and reviewed by The Financial Wire editorial team.
More Financial Reading
- How many CDs can you park at 1 bank? FDIC rules you must know
- Adding someone to your bank account: tax traps and smart moves
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
