ASTRO 2026 | Ultra-Low-Dose Radiation Therapy Assessed for Bone Pain Relief in Multiple Myeloma Patients

In a promising development for multiple myeloma patients, a new study reveals that ultra-low-dose radiation therapy can effectively alleviate bone pain associated with the disease. The findings, presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting, highlight the potential benefits of using a reduced radiation dose to manage pain without significant side effects.

The trial, a multi-institutional phase 2 study, investigated the effects of administering a low radiation dose in one or two sessions to patients with bone lesions from multiple myeloma. Results indicated that 81% of participants experienced significant pain relief, with side effects mainly limited to low-grade fatigue.

Leslie Ballas, MD, FASTRO, the principal investigator and a professor of radiation oncology at Cedars Sinai, explained that multiple myeloma exhibits high sensitivity to radiation therapy. "Our study shows that a very low dose can provide meaningful pain relief for most patients with uncomplicated bone lesions," said Dr. Ballas. "Because this approach is brief and uses a lower dose, it may make clinicians more comfortable referring patients earlier."

Multiple myeloma, a cancer affecting plasma cells within bone marrow, often leads to painful bone lesions. These symptoms can decrease quality of life due to pain and fractures. Radiation therapy traditionally targets these lesions, but concerns about harming healthy bone marrow or treatment scheduling with systemic therapies have delayed its use.

The study aimed to evaluate whether an especially low dose of radiation could provide adequate pain relief. Reflecting similar practices for lymphomas, the trial delivered a total of 4 Gy radiation, either in a single 4 Gy session or split into two 2 Gy sessions.

The study enrolled patients from seven institutions, focusing on those whose bone lesions caused pain without leading to severe complications like spinal cord compression or fractures. Researchers measured pain responses through the Brief Pain Inventory scores and oral morphine equivalents.

By four weeks post-treatment, three in five patients reported pain relief, which increased to four in five within six months. Most notably, the median time to achieve pain relief was 36 days, lasting a median of 148 days. A second radiation course was necessary for 19% of participants, who received it on average 71 days after the initial treatment. Even after reirradiation, the pain response remained strong, at 63% at the four-week follow-up.

For many individuals, this initial course was sufficient, as noted by Dr. Ballas: "Four out of five patients did not need more radiation therapy after the first course, which tells us this strategy can provide effective pain control without interrupting other treatments and with almost no side effects."

Dr. Chelsea Pinnix, a radiation oncologist at the University of Texas MD Anderson Cancer Center, also praised the study. "The findings suggest that many patients can experience meaningful pain relief with a very low initial radiation dose. This approach is convenient for patients and provides excellent pain relief with minimal side effects," she remarked.

As multiple myeloma patients often experience multiple painful lesions, employing this low-dose radiation technique could facilitate earlier intervention, improving pain management while maintaining bone marrow health. Future research will investigate when to best administer low-dose radiation and which lesions respond most effectively to this treatment.