Short radiation course may ease painful myeloma bone lesions

A short course of ultra-low-dose radiation may relieve pain for many people with multiple myeloma who have uncomplicated bone lesions, with minimal side effects, according to new data from a small clinical trial.

The findings may help patients get radiation therapy earlier in the course of treatment, providing relief from pain while other therapies are working to fight the cancer, according to researchers. Results were presented earlier this week at the American Society for Radiation Oncology (ASTRO) Annual Meeting, in a talk titled “Phase II Multi-Institutional Study of Ultralow-Dose (4Gy) Response-Adapted Radiotherapy for Symptomatic Bone Metastases from Multiple Myeloma.”

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“My hope is that these findings will help more multiple myeloma patients get pain relief more quickly,” Leslie Ballas, MD, principal investigator of the trial and a professor of radiation oncology at Cedars Sinai in Los Angeles, said in a press release from ASTRO. “Even though this is a relatively small study, we now have prospective data from multiple institutions showing that this approach can provide meaningful pain relief with minimal side effects, making it a practical and flexible strategy for routine clinical care.”

Myeloma is marked by the abnormal growth of plasma cells in bone marrow, the spongy material inside bones that is responsible for making new blood cells. Bone pain is a common symptom of myeloma.

Often, painful bone lesions are managed with radiotherapy, where a beam of radiation is directed at the affected bone. This can kill myeloma cells and relieve pain, but traditional radiation can also expose healthy bone marrow to treatment, raising concerns about side effects. Plus, it can be difficult to navigate the logistics of radiation alongside other myeloma treatments. Because of these issues, patients often are referred for radiation later in their care, after symptoms worsen.

This study aimed to evaluate whether a very low dose of radiation — 4 gray (Gy) — could relieve pain while limiting exposure to healthy bone marrow and reducing side effects.

“The aim is to start with a dose that is enough to relieve pain but low enough to preserve bone marrow and leave room to add more radiation if needed,” Ballas said. “That flexibility may help patients access radiation therapy earlier in their disease course and still keep future treatment options open.”

The analysis included 63 evaluable people with myeloma who had bone lesions that were painful but were not causing spinal cord compression, a pathologic fracture of a long bone, or other urgent complications. All participants received 4 Gy of radiation, either as one 4-Gy treatment or two 2-Gy treatments.

Pain relief increased over time

Among patients who completed questionnaires, 66% met the study’s criteria for pain relief four weeks after treatment. The rate was 64% at eight weeks and rose to 86% at six months. Median time to pain relief was 36 days, and median duration of pain relief was 148 days, or nearly five months.

“Ultralow dose radiation improved pain and produced durable responses in the majority of patients. The proportion of patients with improved pain increased over time,” the researchers wrote.

Overall, 19% of patients received a second course of radiation to the same site. Among those patients, 63% met the study’s criteria for pain relief four weeks after the second course.

Side effects were rare and mild; four patients experienced mild-to-moderate fatigue, and one reported mild radiation-related skin changes.

Overall, the data suggest that ultra-low-dose radiation may relieve pain with minimal side effects for many patients whose bone lesions are not causing urgent complications, the researchers concluded.

“Multiple myeloma is extremely sensitive to radiation therapy, and our study shows that a very low dose can provide meaningful pain relief for most patients with uncomplicated bone lesions,” Ballas said. “Because this approach is brief and uses a lower dose, it may make clinicians more comfortable referring patients earlier, so their patients don’t have to live with pain while waiting for other treatments to work.”

“As patients live longer and receive more lines of therapy, preserving bone marrow function and reducing time in treatment become more important,” Ballas added. “This study suggests we may be able to address pain, with less treatment, for many patients.”