Low dose radiation therapy for refractory osteoarthritis

Radiation therapy, a mainstay of cancer treatment, is now emerging as a non-invasive, non-pharmacologic alternative for treating osteoarthritis and other musculoskeletal conditions that cause chronic pain.

Recently, Penn Medicine experts Logan Barnes, PA-C, and John Plastaras, MD, PhD, joined the Penn Medicine Physician Interviews podcast to discuss low-dose radiation therapy, an emerging treatment for osteoarthritis pain, now offered through the Penn Functional Radiation Program.

Logan Barnes is a physician assistant at Penn Radiation Oncology at Penn Presbyterian Medical Center. Dr. Plastaras is Chief of Radiation Oncology and Proton Therapy at Penn Presbyterian Medical Center and vice chair of Strategic Clinical Research, Radiation Oncology, at Penn Medicine.

Growing evidence for low-dose radiation therapy

Low-dose radiation for osteoarthritis has been used for decades in Europe, but only recently gained attention in the United States, Dr. Plastaras says. The recent attention arrives at a time of surging interest in noninvasive and safer treatments for osteoarthritis pain. “A lot of patients who may have taken OxyContin for osteoarthritis have been steered away from that, so there’s been a big push to look for alternatives,” he adds.

Although low-dose radiation has a long history for osteoarthritis pain treatment outside of the US, research findings have been mixed. At first a skeptic, Dr. Plastaras reevaluated low-dose radiotherapy when he discovered a growing body of research suggesting that, for carefully selected patients, the treatments can make a real difference. He was particularly impressed by the encouraging results of a large Korean clinical trial presented at the fall 2025 meeting of the American Society for Radiation Oncology.

Among much else, Dr. Plastaras lauds the design of the trial, a three-arm study in patients with moderate osteoarthritis of the knee that evaluated the capacity of very low-dose (0.3 gray) and low-dose (3 gray) radiation versus no treatment (sham) to alleviate osteoarthritis pain.

Patients in the higher-dose arm, who received six doses of 0.5 gray each, saw an improvement rate of 70 percent compared to the sham arm, which experienced improvement of about 40 percent. Patients in the lower-dose arm, who received six doses at 0.3. gray also saw more improvement than the sham group.

The findings in the high-dose arm of the study, Dr. Plastaras says, were both convincing and statistically significant. While the lower-dose arm didn’t match the higher-dose arm for significance, he observes, the improvement in this arm over that of the sham arm was notable because it suggested that even the smallest doses might have an impact.

Beyond osteoarthritis: non-malignant indications for radiation therapy

With the exception of the visit number and length of course, the treatment process for non-malignant indications is similar to radiotherapy for cancer. Patients start with a consultation and a CT simulation, which radiation oncologists use to develop a treatment plan. However, unlike cancer radiotherapy, which can extend daily visits to eight weeks, a typical treatment course of low-dose radiotherapy for osteoarthritis involves twice weekly sessions over three weeks.

Low-dose radiation for osteoarthritis pain at the Penn Functional Radiation Program

Dr. Plastaras, Logan Barnes, and colleagues at Penn Presbyterian Medical Center use low-dose radiation to treat patients with osteoarthritis that has not responded to conservative management in all joints except the spine. Plantar fasciitis is the second-most common indication after osteoarthritis, but the treatment has also been applied to patients with Dupuytren’s contracture and plantar fibromatosis (Ledderhose disease).

“We’re looking for patients that have tried oral medication, physical therapy, cortisone, hyaluronic acid injections, other types of injections, and still have symptoms and limited function,” Logan Barnes says.

Dr. Plastaras adds that his experience of treating osteoarthritis patients with low-dose radiation has been promising. “It really does seem to work. When you have patients who have tried everything, and they get a [radiation] treatment or two and are feeling better and come up to give you a hug, it does feel very real,” he says.

Extending the reach of low-dose radiation therapy

Providers at Penn Medicine’s Functional Radiation Program are also actively involved in research to better understand low-dose radiotherapy to better determine which populations might benefit from it. With a grant from the Radiation Oncology Institute, Penn Medicine experts are planning to do their own prospective trial of low-dose radiation for osteoarthritis.

The team will collect a variety of outcomes measures, including a multidimensional pain score, functional scores that break down into different parts of the body, and quality of life instruments.

“We’re really going to see how this treatment impacts not just pain, but also function,” Dr. Plastaras says.

The trial is unique in that it will explore the treatment in populations that haven’t been studied before, including patients who are metabolically inflamed as a result of conditions such as obesity, diabetes, or pre-diabetes. The study will also include a subgroup of patients with breast cancer who experience musculoskeletal pain due to a class of cancer drugs known as aromatase inhibitors.

“Up to 20 percent of patients with breast cancer who are taking these lifesaving medications actually have to stop due to their pain,” Dr. Plastaras says. “We’re hoping to enroll a certain portion of those in this study to see if low-dose radiation can impact the joint pain that those patients experience.”

The Functional Radiation Program at Penn Medicine

The Penn Functional Radiation Program is centered at Penn Presbyterian Medical Center. But the goal, providers say, is to make this treatment accessible to as many patients as possible. Treatments may be provided at locations closer to patients’ homes, including Cherry Hill, Doylestown, Radnor, Valley Forge, and Chester County Hospital.

Penn Medicine partners closely with referring providers through multidisciplinary evaluation and treatment. The program welcomes patient self-referrals and referrals from inside and outside the Penn system, with a dedicated program coordinator to schedule patients for consultation and treatment.

Referrals and consultations

For a provider-to-provider consultation with Logan Barnes or Dr. John Plastaras, call 877-937-7366, or refer a patient online.