A Korean clinical trial has demonstrated that low-dose radiation therapy significantly reduces pain and improves mobility in patients with mild to moderate knee osteoarthritis, outperforming placebo effects. The treatment, which uses doses far below those for cancer, showed no side effects and could serve as an alternative to medications or surgery. Results were presented at the American Society for Radiation Oncology Annual Meeting.
Osteoarthritis, the most common form of arthritis, affects an estimated 32.5 million adults in the United States, primarily targeting knees and hips as cartilage wears away over time. Standard treatments start with lifestyle changes and pain medications, progressing to surgery for severe cases. Now, a new randomized, placebo-controlled trial from Korea suggests low-dose radiation therapy as a potential middle-ground option.
The multicenter study, led by Byoung Hyuck Kim, MD, PhD, from Seoul National University College of Medicine, Boramae Medical Center, involved 114 participants with mild to moderate knee osteoarthritis recruited from three academic hospitals. Patients were randomly assigned to one of three blinded groups: a very low dose of 0.3 Gy, a low dose of 3 Gy, or a sham control with simulated radiation. Each underwent six treatment sessions, with analgesic use limited to acetaminophen during the four-month follow-up to isolate radiation effects.
Effectiveness was measured using international standards, defining a 'responder' as someone with meaningful improvement in at least two of three areas: pain, physical function, and overall condition. After four months, 70% of the 3 Gy group met responder criteria, compared to 42% in the placebo group (p=0.014). The 0.3 Gy group showed 58.3% improvement, not significantly different from placebo (p=0.157). Composite scores for pain, stiffness, and function improved in 56.8% of the 3 Gy group versus 30.6% in placebo (p=0.024). No radiation-related side effects were observed, with doses less than 5% of typical cancer therapy.
"People with painful knee osteoarthritis often face a difficult choice between the risks of side effects from pain medications and the risks of joint replacement surgery," said Dr. Kim. "There's a clinical need for moderate interventions... and we think radiation may be a suitable option." This approach, long used in Europe like Germany and Spain, lacks prior rigorous placebo evidence. Dr. Kim noted it suits patients with inflammation and preserved joint structure, potentially delaying surgery when combined with weight loss and physiotherapy.
The team is conducting 12-month follow-ups and planning larger trials to assess durability and cost-effectiveness.