- Osteoarthritis is the leading cause of disability among adults, and its management involves physical therapy, painkillers, corticosteroid injections, and surgery.
- A significant number of people with osteoarthritis do not respond to nonoperative treatments or show a decline in responsiveness over time, leaving surgery as the final option.
- Radiation therapy is a noninvasive alternative for the management of osteoarthritis, but high-quality data from clinical trials on its effectiveness is limited.
- A recent randomized controlled clinical trial demonstrated that a single course of low-dose radiation therapy was more effective in reducing pain and improving mobility in individuals with mild to moderate knee osteoarthritis at 4 months after treatment than the control group that did not receive radiation therapy.
- These results suggest that low-dose radiation therapy could help delay or prevent surgical interventions in individuals with osteoarthritis.
The first line of treatment for osteoarthritis includes physical therapy and oral medications but procedures such as direct injection of medications into the joint and surgery are necessary in more severe cases.
Radiation therapy or radiotherapy is an underutilized noninvasive treatment option for osteoarthritis, but data from clinical trials have been mixed.
Data from a randomized controlled clinical trial conducted in South Korea now show that individuals with mild-to-moderate knee osteoarthritis were more likely to experience improvement in pain and mobility at 4 months after receiving a single course of low-dose radiation therapy than their counterparts who received sham treatment.
The study’s author, Byoung Hyuck Kim, MD, PhD, an assistant professor of radiation oncology at the Seoul National University College of Medicine, said in a press release that:
“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. There’s a clinical need for moderate interventions between weak pain medications and aggressive surgery, and we think radiation may be a suitable option for those patients, especially when drugs and injections are poorly tolerated.”
The study’s results were recently shared at the American Society for Radiation Oncology conference in San Francisco, and they are yet to undergo peer review.
Osteoarthritis is characterized by the gradual degeneration of the joints, leading to pain, swelling, and reduced joint mobility. Osteoarthritis typically affects joints in the hands, hips, knees, and spine.
Osteoarthritis cannot be reversed, and its treatment involves preventing disease progression and reducing pain and stiffness. These treatments include lifestyle modifications, physical therapy, and medications.
Medications in the initial stages involve the use of oral or topical
Long-term use of NSAIDs is associated with adverse effects, including increased risk of gastrointestinal issues and cardiovascular diseases. Moreover, a significant number of individuals do not respond to these treatments or show a decline in responsiveness over time.
Surgery is the treatment of last resort in individuals who fail to respond to other treatments. Radiation therapy is a noninvasive alternative for the treatment of osteoarthritis that has been underutilized. Besides its use in cancer treatment, radiation therapy has been used for the treatment of benign musculoskeletal conditions.
Radiation therapy for cancer treatment involves the use of high doses of radiation to kill the cancer cells. In contrast to cancer treatment, radiation therapy for conditions like osteoarthritis involves the use of low doses of radiation.
Inflammation of the joints occurs at the onset of osteoarthritis, and this inflammatory environment leads to the degradation of the joint tissue by enzymes. Low doses of radiation, such as those used in osteoarthritis treatment, exhibit anti-inflammatory effects and also help reduce pain.
While low-dose radiation therapy is used in the clinic for osteoarthritis in Europe, its use in clinics in the United States for osteoarthritis declined in the 1980s after the development of new medications. Moreover, there is limited data from randomized clinical trials on the effectiveness of low-dose radiation therapy for treating osteoarthritis, and the existing data are mixed.
In the recent study, Kim and his colleagues examined the effectiveness of low-dose radiation therapy in treating individuals with mild to moderate arthritis in a recent randomized, sham-controlled clinical trial.
In the aforementioned clinical trial, researchers recruited 114 patients with mild to moderate knee osteoarthritis and randomly assigned the patients to three groups. The participants allocated to the control group received sham or simulated radiation, undergoing all the procedures involved during radiation therapy without being exposed to radiation.
The patients in one of the experimental groups received 3 Gray (unit of radiation) of total radiation, whereas the other group received a lower dose of 0.3 Gray.
The participants in each group received either sham radiation or radiation in 6 small doses. This clinical trial was a single-blind study, with participants remaining unaware whether they had received sham or real radiation during the trial. This masking of group identity was done to reduce the risk of bias.
The researchers asked the participants to avoid the use of strong painkillers, such as NSAIDs, during the follow-up period, to prevent these medications from obfuscating the effects of the radiation therapy. The participants were only allowed to use acetaminophen during this time.
Kim noted that this made the study stand out from other clinical trials. In the press release, he said that: “In previous studies, drugs such as NSAIDs or opioids were also used during the intervention or follow-up period. But using these pain relievers could mask the effects of radiation therapy.”
After a 4-month follow-up period, the researchers classified the patients as either responders or nonresponders based on standardized criteria that take into account changes in pain, function, and the participants’ assessment of overall symptoms.
A higher proportion of participants (70%) receiving the higher 3 Gray dose qualified as responders after the follow-up period than those in the control group (41%).
The group receiving the lower dose of radiation therapy had a similar rate of patients showing improvements in symptoms to that in the control group.
Based on the participants’ responses to a standardized questionnaire, the researchers also observed greater improvements in self-reported composite scores of pain, stiffness, and function in the higher-dose group than in the sham control group.
No radiation-related side effects were observed in the treatment groups. Participants in this ongoing clinical trial will be monitored for 12 months after treatment onset to assess the durability of the therapeutic effects of the single low-radiation therapy course. The researchers also intend to conduct imaging studies to understand the impact of radiation therapy on joint structure and inflammation.
In the press release, Kim noted that radiation therapy would most likely benefit individuals with mild to moderate osteoarthritis who have an intact joint structure.
“For severe osteoarthritis, where the joint is physically destroyed and cartilage is already gone, radiation will not regenerate tissue. But for people with mild to moderate disease, this approach could delay the need for joint replacement.”
– Byoung Hyuck Kim, MD, PhD
In addition, the researcher observed that low-radiation therapy could be more effective when used in combination with other treatments, such as physical therapy and medication, noting that, “in clinical practice, responses could be even stronger when radiation is properly combined with other treatments, and patient satisfaction may be higher than with current options alone.”
The use of low-dose radiation therapy carries the risk of causing cancer in the long term, but several studies have shown an absence of increase in cancer incidence after low-dose radiation therapy.
James Yu, MD, a radiation oncologist at Dartmouth Cancer Center, who was not involved in this study, told Medical News Today: “Given the theoretical potential for radiation-induced cancers, I believe that patients should be generally over the age of 60.”
Evidence suggests that a second dose of radiation therapy can be effective in alleviating pain in osteoarthritis patients who do not respond to the initial treatment or show reemergence of symptoms.
Yu pointed out that the participants receiving the higher dose (3 Gray) of radiation therapy who did not respond to the treatment could be candidates for a second course of radiation therapy.
“In the 30% nonresponders, I think physicians and patients can consider repeat treatment if there is still pain 3-4 months after treatment,” he said.
