Low-dose radiation therapy is best known as a powerful tool against cancer. Now researchers are exploring a very different use for it: easing osteoarthritis pain in people who have had breast cancer, particularly those whose joint problems flare as a side effect of treatment. This emerging approach, often described as low-dose radiation for osteoarthritis, may help some patients stay on crucial therapies such as immunotherapy and hormonal treatment, while improving daily comfort and mobility.

At UT MD Anderson Cancer Center in Texas, a new clinical trial will soon examine how well low-dose radiation can relieve osteoarthritis in the knees and hips of people treated for breast cancer who develop painful arthritis flares during immunotherapy. Osteoarthritis is a degenerative joint disease that wears down cartilage and can damage the underlying bone, so it frequently leads to chronic pain and stiffness. For people already navigating breast cancer, this extra burden can make everyday life even more difficult.

The trial will be led by Chidinma Anakwenze, MD, MPH, an assistant professor of radiation oncology at UT MD Anderson. The study focuses on a specific group: people with breast cancer whose arthritis symptoms worsen during cancer treatment to the point that they may consider stopping or adjusting their therapy. Stopping a recommended cancer medicine because of side effects is a complicated and often distressing decision, and researchers hope this new approach can help some avoid that crossroads.

Osteoarthritis is relatively common in people with breast cancer, and the condition can be triggered or worsened by the very treatments designed to keep cancer in check. Hormonal therapies, particularly aromatase inhibitors, are known to increase joint pain and stiffness for some. Immunotherapy and other systemic treatments can also contribute to or aggravate existing joint problems. When pain becomes severe enough, some individuals feel they have little choice but to pause or discontinue medications that are important for long-term cancer control.

Treating osteoarthritis in this context can be challenging. Many standard therapies either do not provide enough relief or come with trade-offs that are especially problematic for someone receiving cancer treatment. Steroid injections often work only temporarily and may need to be repeated in the same joint, where frequent injections can eventually harm the tissue. Oral or intravenous steroids carry another concern for those on immunotherapy because systemic steroids can weaken the immune response that immunotherapy is meant to activate. Joint replacement surgery is a more invasive option that not everyone is ready or medically able to pursue.

Anakwenze and colleagues believe low-dose radiation may offer another path. She explains that this approach might not only relieve current inflammation in the joint but could also help reduce future flares in the treated area. By calming the immune activity around the joint, it may be possible to let patients continue immunotherapy without being forced to stop because of pain. Early experience at UT MD Anderson and other centers has been encouraging enough that the team felt a dedicated clinical trial in people with breast cancer was warranted.

Although low-dose radiation for osteoarthritis is not widely known in the United States, it has been used for decades in parts of Europe. The same machines that deliver high-dose radiation for cancer treatment, such as linear accelerators, are used, but at a far lower dose. The radiation given for osteoarthritis is about 90 to 95 percent lower than what is typically used to treat a tumor. This gentler level of exposure is designed to reduce inflammation rather than destroy cancer cells.

The treatment itself is noninvasive. Patients visit a radiation oncology clinic, where the medical team positions the affected joint under the linear accelerator. High-energy X-ray beams are directed carefully at the joint from one or more angles, tailored to the anatomy of the area. A usual course is given every other day for six sessions. If the first course does not bring sufficient relief, a second series of six treatments may be offered about three months later, sometimes using a slightly higher dose within the low-dose range.

Reported side effects from low-dose radiation for osteoarthritis are uncommon, and when they do occur they tend to be mild. Some people notice slight skin irritation over the treated area or temporary fatigue. Serious complications are rare, although there is a small lifelong risk of developing a second cancer related to radiation exposure. That risk is one reason the therapy is generally reserved for adults age 50 and older who have had breast cancer, and it is used more cautiously in younger individuals.

At UT MD Anderson, candidates for this approach usually have mild to moderate osteoarthritis in joints such as the shoulders, knees, hips, wrists, or hands. The spine is not currently being treated with this method at that center. Eligible patients typically have not experienced adequate relief from standard measures such as physical therapy and non-narcotic pain medications, and they have not yet undergone joint replacement surgery in the area being considered for radiation. Exceptions may be made in certain situations, for example for younger people with metastatic breast cancer who have severe arthritis symptoms and few remaining options.

Previous research, including experience in Europe and data from MD Anderson’s own patients, suggests that low-dose radiation therapy for osteoarthritis can be highly effective for many. Anakwenze reports that about 70 to 80 percent of patients with mild to moderate osteoarthritis treated at UT MD Anderson have had a meaningful improvement in their symptoms. Pain relief often begins within a few weeks after treatment ends, occasionally even within a few days. For some, the benefits last six months; others report relief that continues for two or three years.

People with more advanced osteoarthritis tend to be more likely to need a second course of radiation to maintain or deepen the effect. Even so, many treated patients have described striking changes: standing up from a chair more easily, giving up a cane, or postponing a knee replacement that once seemed inevitable. I found this detail striking because it highlights how even modest changes in pain and function can transform daily routines, especially for those already dealing with the physical and emotional demands of breast cancer.

The new PRAISE-BC clinical trial at MD Anderson is scheduled to open for enrollment in January 2027 at several locations in the Houston area. It will focus specifically on people with breast cancer who experience osteoarthritis flares related to immunotherapy, aiming to measure not only pain relief and physical function but also whether patients are better able to continue their cancer treatment as planned.

Beyond the trial, low-dose radiation therapy for osteoarthritis is becoming available at a growing number of radiation oncology clinics in the United States. In many cases, insurance may cover the treatment when prescribed by a physician and when the person meets criteria similar to those used at MD Anderson. Anyone living with osteoarthritis after breast cancer who is interested in this option can start by speaking with their primary care clinician, medical oncologist, radiation oncologist, orthopedic surgeon, or palliative care specialist. These professionals can help determine whether the therapy is offered locally and whether it might be a suitable part of a comprehensive care plan.

Low-dose radiation is not a cure for osteoarthritis, and it will not replace every other therapy. Yet for some, it may provide another valuable option to reduce pain, improve mobility, and support continued cancer treatment. As more data emerge from trials like PRAISE-BC, clinicians and patients will have better guidance on when and how to use this approach so that more people can benefit from safer, more comfortable long-term care after breast cancer. Read more at https://www.breastcancer.org/news/low-dose-radiation-osteoarthritis