ASTRO 2026 | Potential Role of Low-Dose Radiation Therapy in Managing Knee Osteoarthritis

Emerging research suggests that low-dose radiation therapy may significantly alter the progression of knee osteoarthritis, offering more than just symptomatic relief. This insight stems from a comprehensive analysis of a longitudinal study conducted in Russia, which monitored nearly 300 patients for close to 12 years.

Participants in the study who received low-dose radiation therapy exhibited sustained enhancements in pain relief, physical functionality, and overall quality of life compared to those who only received medication. MRI assessments revealed a noticeable reduction in structural deterioration in the knees of those treated with radiation. Statistically, the therapy was associated with a 67% lower adjusted hazard of government-certified disability attributed to knee osteoarthritis. Notably, the most pronounced effects were witnessed in individuals with grade 2 osteoarthritis.

Dr. Bobby (Nagendra) Koneru, a radiation oncologist at Loyola University, highlighted the comprehensive nature of the study's outcomes. "Patients experienced sustained improvements in pain and function, MRI showed less joint deterioration, and years later, we saw reduced disability and fewer knee replacements in grade 2 patients," he noted.

Typically, knee osteoarthritis treatments focus on alleviating symptoms through exercise, weight management, and medications or injections. However, these methods often fail to significantly slow down disease progression. Low-dose radiation therapy, widely used in certain parts of Europe and increasingly in the U.S., leverages smaller doses compared to cancer treatments to reduce inflammation and manage pain from osteoarthritis.

The study's cohort included 292 patients with knee osteoarthritis classified as Kellgren-Lawrence grade 0, 1, or 2. Participants were randomly assigned to receive either glucosamine and chondroitin alone or alongside low-dose radiation therapy. The radiation regimen consisted of 4.5 Gy administered through low-energy x-rays over ten treatments.

The benefits of radiation therapy were not only immediate but also long-lasting, as the treated group reported superior improvements in physical function and life quality. MRI evaluations conducted over a three-year period post-treatment corroborated these improvements, revealing less structural deterioration compared to the medication-only group.

An exploration of the regional health records demonstrated that radiation therapy significantly lowered the long-term risk of disability. The greatest benefits were observed in patients with grade 2 osteoarthritis, where only 14% of radiation-treated individuals underwent knee replacement compared to 36% in the control group.

The findings prompt an important discussion on the potential of low-dose radiation therapy to serve as a disease-modifying treatment rather than solely a symptom management tool. However, Dr. Koneru emphasized the need for further research to confirm these promising results in broader, multicenter studies.

While the study provides compelling evidence, Dr. Koneru acknowledged its limitations, including the unblinded nature of treatment allocations and variations in health care delivery between regions, which could influence the applicability of results widely.

The study advocates for expanded research, proposing a multicenter randomized trial to rigorously evaluate the long-term benefits and safety of low-dose radiation therapy in managing knee osteoarthritis, especially among patients with grade 2 disease.