ASTRO 2026: Can Ultra–Low-Dose Radiotherapy Relieve Bone Pain From Multiple Myeloma?
By: Julia Cipriano, MS, CMPP
Posted: Friday, October 9, 2026
Ultra–low-dose, response-adapted radiotherapy provided durable pain relief in most patients with symptomatic bone metastases from multiple myeloma, according to findings from a multi-institutional phase II trial presented at the 2026 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 10). Leslie Ballas, MD, FASTRO, of Cedars-Sinai, Los Angeles, and colleagues reported that pain response rates increased over time, with relatively few patients requiring reirradiation.
“This response-adapted approach allowed for selective augmentation of pain control with minimal toxicity,” the investigators commented.
In this single-arm study, 63 evaluable patients with 70 uncomplicated painful bone lesions received either 2 Gy in two fractions or 4 Gy in one fraction. The primary endpoint was patient-reported pain response at 4 weeks, assessed using the Brief Pain Inventory (BPI) and oral morphine equivalent dosing, with additional assessments at 8 weeks and 6 months. Reirradiation with clinician-choice regimens could be considered for inadequately controlled pain.
Pain response rates (complete or partial responses) among patients who completed questionnaires were 59% (intention-to-treat [ITT] analysis: 57%) at 4 weeks, 63% (ITT: 47%) at 8 weeks, and 82% (ITT: 53%) at 6 months. Median reductions in BPI scores were 2.25 and 2.75 points at 4 and 8 weeks, respectively, with corresponding reductions in oral morphine equivalent dosing of 5 and 6.2 mg. Patients experienced pain relief after a median of 36 days, with a median response duration of 148 days. Pain relief did not appear to differ by fractionation regimen.
Less than a quarter of patients (24%) underwent reirradiation at a median of 71 days after initial treatment, receiving a median dose of 20 Gy. After reirradiation, the 4-week pain response rate was 63%, with a median time to pain relief of 95 days. No treatment-related toxicities of grade 3 or higher were reported.
Disclosure: For full disclosures of the study authors, visit amportal.astro.org.
