A University of Chicago analysis projects that new federal Medicaid restrictions will cause roughly 680,000 missed colorectal cancer screenings nationwide over two years — and California's safety net, already bracing for hundreds of thousands of newly uninsured residents, is where that math will play out.

Two forces are converging on low-income Bay Area residents at once: the Medicaid work requirements and re-verification rules in H.R. 1, the reconciliation law President Trump calls the "One Big Beautiful Bill," and the separate expiration of the enhanced Affordable Care Act premium subsidies on Jan. 1. Preventive care is the first thing to fall out when coverage lapses — and colorectal cancer, one of the most survivable cancers when caught early, depends on exactly the kind of routine screening that uninsured people skip. The result, health researchers warn, is a slow-moving crisis: fewer screenings now, more late-stage diagnoses later.

A "thousand things" went through Nancy Villena's mind, SFGATE reported, when the Petaluma Health Center called three years ago to say her stool test was abnormal. She had no symptoms and no insurance. The clinic connected her to Operation Access (external source, opens in a new tab), a San Francisco nonprofit that routes low-income, uninsured Northern Californians to providers who donate procedures like colonoscopies. Nine polyps were found and removed. In the outlet's account, she credited the nonprofit with the years she now gets to spend with her children and grandchildren.

Villena is the case that works. The concern among clinicians and researchers is how many future patients never get the call — because they never got screened.

A research letter published Jan. 8 in JAMA Oncology (external source, opens in a new tab) by University of Chicago surgical oncologists Sarah Shubeck and Adrian Diaz put numbers to that fear. Modeling the Medicaid work requirements and six-month re-verification rules in H.R. 1, they project nearly 1.2 million missed screenings for breast, colorectal and lung cancer over two years among the 7.5 million people expected to lose coverage — including about 680,000 missed colorectal screenings (external source, opens in a new tab). Their model estimates 155 preventable deaths.

A "thousand things" went through Nancy Villena's mind, SFGATE reported, when the Petaluma Health Center called three years ago to say her stool test was abnormal.

Diaz, in an interview with STAT News, made the clinical stakes plain: most of his cancer patients arrive without symptoms and are diagnosed only because a screening test caught the disease early, when it is still treatable or curable — the exact window this policy would close for many. The new Medicaid requirements take effect Jan. 1, 2027; the researchers built their model from Arkansas's 2018 work-requirement rollout and pandemic-era disenrollment data, then scaled it nationally.

The screening gap is not theoretical. Uninsured adults are far less likely to be screened for colorectal cancer than insured ones — a disparity the outlet noted from a 2023 national survey, in which 23% of uninsured people completed screening versus 62% with private coverage. When insurance disappears, so does the primary-care visit where a doctor orders the test in the first place.

California will absorb an outsized share. The Congressional Budget Office estimates H.R. 1 will add about 10 million to the ranks of the uninsured (external source, opens in a new tab) nationally by 2034 while cutting more than $1 trillion in federal health spending. Layered on top, the enhanced ACA premium tax credits from the 2022 Inflation Reduction Act expired Jan. 1 (external source, opens in a new tab), leaving roughly 1.7 million Californians in the individual market facing premium spikes. The state moved $190 million to soften the blow — a fraction of the $2.5 billion in enhanced federal subsidies Golden State enrollees received in 2025 — and Covered California still projects up to 400,000 people could become uninsured (external source, opens in a new tab).

Those losses do not land evenly. They concentrate among the low-income, immigrant and Black and Latino residents who already screen at the lowest rates — the same population that clinics like Petaluma Health Center and nonprofits like Operation Access exist to reach. Operation Access serves patients regardless of immigration status and up to modest income limits; every colonoscopy it arranges is donated. That model scales only so far, and it was built to fill gaps in the safety net, not to replace it.

The policy timeline gives the region a narrow window. The Medicaid work requirements are still phasing in, and the screenings not done in 2026 and 2027 will not surface as diagnoses until years later — by which point, researchers warn, they are more likely to be advanced, more expensive to treat and less likely to be survivable. The cost of the cut, in other words, is deferred. It just isn't avoided.