More than two thirds of US counties — home to over 50 million people — lacked a radiation oncology practice site in 2025, according to a national analysis of Medicare data. The analysis also found that, between 2018 and 2025, freestanding (community-based) radiation oncology practice sites had higher odds of disappearing than hospital-affiliated sites, whereas practice sites in rural counties had higher odds of disappearing than those in urban counties.

The findings raise concerns that patients with cancer in already underserved communities may face growing barriers to accessing radiation therapy.

The “clearest practical consequence” is the increasing travel burden facing patients in rural communities, senior author Kunal Sindhu, MD, radiation oncologist at the Icahn School of Medicine at Mount Sinai in New York City, told Medscape Medical News. Urban counties that lost practice sites generally retained multiple radiation oncology options, whereas many rural counties were left with no radiation oncology practice site, Sindhu said.

This is a problem, Amar Rewari, MD, MBA, chair of the Health Policy Council for the American Society for Radiation Oncology, told Medscape Medical News.

“For many patients, radiation therapy is not a single appointment. It often means coming in every weekday for several weeks,” said Rewari, who was not involved in the study.

If the nearest treatment center suddenly ends up being 1 or 2 hours away, that is not simply an inconvenience. “For some patients, it becomes the deciding factor in whether they can realistically complete treatment,” said Rewari, chief of radiation oncology at Luminis Health in Annapolis, Maryland, and adjunct assistant professor of radiation oncology at Johns Hopkins University School of Medicine in Baltimore.

The study, published online earlier this month in the International Journal of Radiation Oncology, Biology, Physics, analyzed Centers for Medicare & Medicaid Services data from 2018 to 2025, identifying more than 3100 unique radiation oncology practice sites across the US. The researchers examined predictors of practice-site disappearance and assessed how practice-site losses affected county-level access to radiation therapy.

By 2025, 2154 US counties — 68.5% of all counties — lacked a radiation oncology practice site.

Nationally, 427 US counties (13.6%) experienced a net loss of radiation oncology practice sites during the study period compared with 232 counties that experienced net growth.

In multivariable analyses, freestanding practice sites had 56% higher odds of disappearing than hospital-affiliated sites over a 2-year period, whereas practice sites in rural counties had 44% higher odds of disappearing than those in urban counties.

The pattern of practice-site losses differed dramatically by geography. More than 70% of counties with net losses were in the South and Midwest. Urban counties that lost practice sites still retained an average of 3.66 radiation oncology sites in 2025, whereas rural-adjacent counties retained just 0.43 sites and rural-nonadjacent counties retained only 0.28 sites on average. Rural counties also had substantially lower treatment-site density, suggesting longer travel distances.

Compared with counties that had at least one practice site in 2025, counties without a site had somewhat higher poverty and uninsured rates, lower median household incomes, and substantially fewer primary care physicians. More specifically, counties without vs with radiation oncology access had poverty rates of 14.9% vs 13.4%, uninsured rates of 12.2% vs 10.1%, median household incomes of about $55,000 vs nearly $65,000, and only 4.0 vs 7.2 primary care physicians per 10,000 residents.

Although the study did not examine patient outcomes directly, Sindhu said the findings identify “the structural preconditions for harm,” noting that a growing body of research has linked longer travel distances to radiation therapy facilities to worse cancer outcomes, including higher rates of mortality.

“Unfortunately, the access gap is real and growing in some of the most vulnerable places in the United States,” Sindhu said.

That means bringing potential barriers to receiving healthcare into the conversation earlier is important for physicians caring for patients in underserved areas, Rewari said.

“If transportation, work responsibilities, or caregiver support are likely to interfere with [radiation oncology] treatment, it is much better to identify those before treatment decisions are finalized than after,” he said.

Although the study did not evaluate whether payment reform would reduce practice-site losses, Rewari pointed to the proposed bipartisan Radiation Oncology Case Rate (ROCR) Act as one potential long-term approach. The bill would shift Medicare reimbursement from payment per treatment to episode-based payments intended to provide greater payment stability.

“Unfortunately, our payment system has not evolved” alongside advances in radiation therapy, which has become more precise and efficient, Rewari said. “In some cases, doing what is best for the patient can create greater financial pressure on the practice. That is exactly backwards.”

However, Rewari cautioned that ROCR alone will not solve today’s access challenges.

“Practices that are struggling today still need near-term solutions while broader payment reform is implemented. Preserving access requires both short-term stabilization and long-term reform,” he said.

The study has no funding source. Disclosure information for the study authors is available with the original study publication. Rewari had no relevant disclosures.