Increasing numbers of radiation oncologists are now offering low-dose radiation for osteoarthritis in the hands, feet, knees, shoulders, elbows and hips, saying it’s becoming a viable option for patients seeking a non-invasive management approach.
Medscape Medical News reports that the first time Anna Shapiro, MD, Professor of Radiation Oncology at SUNY Upstate University Hospital in Syracuse, New York, had treated osteoarthritis with low-dose radiation was after a retired physician approached her with a stack of research requesting it.
“He had limited use of his thumb from arthritis in his joint, and brought me the literature and asked, ‘Would you do this for me?’” she said.
She had already read some of that research herself, including the protocol, and she agreed. “He did very well. He kept moving his hand, (saying), ‘I can use my hands’. He was so happy.”
The experience led Shapiro to delve deeper into the treatment option, even travelling to Germany, where much of the research comes from, to take a course on it.
She is among a growing number of radiation oncologists offering the treatment, and awareness in the field is growing rapidly.
“We’re trying to educate rheumatologists that it’s an option,” Shapiro said. “Radiation oncology sounds as if we only treat cancer, but we actually treat a lot of other benign conditions with radiation.”
While this therapeutic approach had been new to Shapiro, she soon discovered it’s not actually “new” at all.
“It falls into the category of everything old is new again,” she said.
“Radiation for arthritis was used as long as radiation has been available.”
Indeed, the treatment’s first published use was in 1898, Austin Kirschner, MD, PhD, associate Professor of Radiation Oncology at Vanderbilt University in Nashville, Tennessee, told Medscape Medical News.
“It was widely used in the US and Europe through much of the 20th century, but its use declined in the US in the 1970s and 1980s as new pharmacologic options became available and concerns about radiation risks emerged,” he said.
But it remained a standard osteoarthritis treatment in several European countries, especially Germany.
Today, as clarity about the relatively low risk for malignancies from exposure has become evident and the strength of evidence on radiation’s effectiveness for osteoarthritis has grown, awareness of the treatment option is increasing on the Western side of the Atlantic among rheumatologists, primary care doctors, orthopaedic surgeons, interventional anaesthesiologists, and physical therapists.
“I don’t know who’s driving it necessarily; the rheumatologists with whom I’ve worked are very excited because their hands are tied at a certain point with a lot of their osteoarthritis patients,” Robert Reznik, MD, Assistant Professor of Radiation Oncology at Cedars-Sinai Medical Centre in California, told Medscape Medical News.
“They’re willing to try this. The benefits, especially for desperate patients suffering from pain and swelling and the limitations in range of motion, far outweigh the risks.”
No national data exist on how widely the treatment is used in the US – Kirschner said it’s unclear how many patients receive the treatment or how often referrals occur – but many major academic institutions now offer it, as well as a smattering of community clinics countrywide.
“When we discuss the treatment with colleagues, they are usually enthusiastic,” Kirschner said. “Physicians are glad to learn about another treatment option with a non-invasive management approach. They want to exhaust every non-surgical option and ensure patients get the maximum quality of life and the minimal risks of the treatment.”
Older patients ideal candidates
Current options for osteoarthritis before joint replacement include disease-modifying agents, anti-inflammatories, physical therapy, steroid injections, and lifestyle modifications, like weight loss and exercise.
Ideally, those seeking radiation therapy have radiographically confirmed osteoarthritis with persistent symptoms – a pain score of at least 4 out of 10 – after having exhausted all of these options for which they aren’t contra-indicated.
“Radiation falls somewhere between when the patient has tried other conservative measures [but is not] quite ready for joint replacement,” Shapiro said.
It’s also most effective for mild-to-moderate osteoarthritis, where patients still have some partially healthy joint architecture and have not yet progressed to bone-on-bone arthritis, by which point radiation is unlikely to be as effective.
“It may help with decreasing inflammation, but it will be more effective if you catch it earlier,” Shapiro said.
The most appropriate candidates are older than 40 or, more conservatively, older than 50, to reduce the risk for later malignancies, even though that risk remains extremely low, Kirschner said.
In a 70-year-old man who receives low-dose radiation treatment for his knee, the estimated lifetime risk for a radiation-induced cancer is around 0.03%, and even that may be an overestimation because it’s derived from whole-body exposure.
But risk is higher in younger patients or for joints near radiosensitive organs, Kirschner added.
Durable, with little risk
There are multiple different mechanisms by which the treatment is theorised to work, Kirschner noted. “Radiation modulates immune cell function, reduces pro-inflammatory cytokines, polarises macrophages toward an anti-inflammatory phenotype, and decreases oxidative stress on the joint, which differs from how nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids target specific inflammatory pathways or mediators,” he said.
The plain language that Reznik and Shapiro use in describing the mechanism to patients is that the radiation halts the “inflammatory cascade” that contributes to osteoarthritis.
Kirschner, who was senior author on a 2022 review of low-dose radiation for osteoarthritis, said multiple retrospective and prospective studies, mostly from Europe, show moderate- to long-term pain relief with mobility and quality-of-life improvements in about 60%-90% of patients.
“Many large case series and cohort studies show promising pain relief and improved joint function with minimal side effects,” said Bruce McGibbon, MD, Associate Professor of Therapeutic Radiology at Yale School of Medicine, and Medical Director of Radiation Oncology at Greenwich Hospital, Connecticut.
“So, it’s definitely something to consider for patients over 65 with refractory osteoarthritis. And as randomised trial results become available, the potential use cases could grow significantly.”
Results from randomised controlled trials are far more limited and have been mixed, but a handful show promise, with several other trials starting or ongoing.
A 2023 Russian study of 292 patients with knee osteoarthritis cut the risk for disability in half among those receiving radiation and pharmacology (hazard ratio, 0.49; 95% CI, 0.26-0.95) compared with those receiving pharmacology alone.
Over a decade of follow-up, 90% of those who underwent radiation had no disability compared with 80% in the control group. In a smaller 2025 study from Iran, 60 patients aged 65 or older had a baseline pain score of 9/10 for knee osteoarthritis.
The radiation group’s pain dropped to 6/10 (P < .001), whereas there was no significant change in the sham group’s pain scores. In the intervention group, 85% of patients also reported less use of pain medication and improvements in performance status.
The pain relief can last from months to years, with studies reporting that 30%-60% of patients maintain significant pain reduction one-two years after treatment, Kirschner said. Patients do not typically experience acute side: rarely, they may have some slight redness, milder than a sunburn, on the skin of the area radiated.
So far, although malignancy induced by osteoarthritis radiation treatment remains a small theoretical risk, no cases of secondary malignancy have been reported in research for patients over 40.
Still, not all clinicians are convinced the benefits are worth the risk, given other available treatment options.
The American College of Rheumatology has yet to recommend low-dose radiation treatment, and it is not considered a standard of care, Bibi Ayesha, MBBS, Associate Professor of Rheumatology and Director of the Vasculitis Clinic at Montefiore Medical Centre and Albert Einstein College of Medicine in New York told Medscape Medical News.
“There is very limited literature for consensus guidelines for treatment planning of this low-dose radiation therapy for osteoarthritis. Any exposure to radiation can cause an autoimmune shift that can potentially increase your [risk] for cancer,” she said.
Meanwhile, the range of alternative options includes joint braces, NSAID creams, and other topical pain relievers. “Why would you want to expose your patient to radiation when you have other treatment choices?”
Hands, shoulders, knees and toes
While no consensus guidelines from a US medical society exist for low-dose radiation for osteoarthritis, radiation oncologists who offer the treatment follow guidelines from the German Society for Radiation Oncology. The most commonly treated joints are hands, feet, shoulders, knees, hips, elbows, and toes, nearly all extremities where the risk for radiation exposure resulting in malignancy is lower than if it were directed somewhere with more organs.
“One of the most common areas where radiation can make a difference is hands and feet, because orthopaedics doesn’t have offer much for small joints, and, functionally, it affects patients hugely.”
Shapiro said clinicians avoid treating arthritis in the spine with radiation because bone marrow production is still occurring there, even in older patients.
“We worry a little bit more about causing leukaemia because [it] has a shorter latency period between radiation exposure and potential development of a malignancy,” she said.
Although some clinicians also treat arthritis in the ankles, the German guidelines do not currently recommend the therapy for ankle joints.
The treatment protocol begins with an initial consultation, followed by a CT scan to determine the affected area and plan the treatment. Patients then receive six treatments of 0.5 Gy each, conducted two to three times a week over two-three weeks.
Each treatment lasts about 15 minutes and carries the radiation exposure equivalent of “probably a few CT scans”, Reznik said.
Shapiro re-evaluates her patients three months later, and if they had an incomplete pain response, the course can be repeated. Kirschner said about half of those who did not respond to an initial course will respond to a second round three months later.
Shapiro said her first patient’s physical therapist was so impressed with the results he told other patients about it, “so there’s a lot of word of mouth going around”. And as baby boomers continue ageing, demand may grow as well, she and Kirschner said.
Because only radiation oncologists can offer the treatment, they need to balance offering the option with their usual caseload of cancer patients.
“Considering how prevalent arthritis is and our ageing population, there’s a lot of opportunity to expand, but we have to do it thoughtfully and really educate referring doctors,” Shapiro said.
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