Three research teams from San Francisco have reported that low-dose radiation therapy offers a safe and effective treatment option for individuals suffering from mild to moderate arthritis. The findings were presented at the annual meeting of the American Society for Radiation Oncology.
A randomised clinical trial conducted in South Korea involved 114 volunteers with knee arthritis. Participants who received three grays (Gy) of radiation across six sessions experienced a significant reduction in pain and an improvement in physical function. By comparison, radiation doses commonly used to treat cancers such as breast or head and neck cancer typically range between 45 and 60 Gy.
After four months, the study found that 70% of participants who received the low-dose radiation showed measurable improvement in at least two of three key indicators — pain, physical function, and overall condition — compared with 42% of those who underwent a placebo procedure. However, an ultra-low dose (0.3 Gy) was found to be no more effective than placebo.
In a separate analysis conducted by U.S. researchers, 84% of 103 patients treated with low-dose radiation for arthritis in the hands, knees, or other joints reported pain relief. The degree of improvement was consistent across different joints, body weights, and genders.
Dr. Byung Hyuk Kim of Seoul National University College of Medicine, who led the Korean study, explained that low-dose radiotherapy has been routinely used in Europe to treat joint pain, but high-quality, randomised evidence has been limited until now. He added that radiation doses used for arthritis are much lower than cancer treatment levels, and that the targeted joints are typically far from vital organs, which minimises the risk of side effects.
German researchers also tracked more than 4,600 elderly patients who underwent radiation therapy for arthritis between 1994 and 2010. Over 15 years of follow-up, they identified only three cases of solid tumours potentially linked to treatment — two of which were basal cell skin cancers. The team concluded that low-dose radiation for musculoskeletal pain in older adults carries a very minimal risk of inducing malignant tumours.
However, the data also revealed that 1.4% of patients developed leukaemia, particularly when radiation was directed near the bone marrow, where blood cells are produced. As a result, researchers advise caution when applying the treatment to areas near the shoulders or torso.
