By Austin Sim, MD, JD, The Ohio State University Comprehensive Cancer Center
Standard palliative regimens have long been home when using radiotherapy to treat lesions associated with multiple myeloma, and definitive courses have been the same for solitary plasmacytomas.
Ballas et al. report a provocative multi-institutional Phase II study using ultralow-dose response-adapted radiotherapy for symptomatic bone lesions in patients with multiple myeloma. This single-arm study treated patients with an uncomplicated bone lesion to a total dose of 4 Gy in either one or two fractions and had a primary endpoint of clinical pain response using both the Brief Pain Inventory (BPI) and Oral Morphine Equivalent Dosing (OMED) at various time points (four weeks, eight weeks, six months). With 70 treated lesions in 63 patients across seven institutions, an objective pain response was seen in the majority of patients (66% at four weeks, 64% at eight weeks and 86% at six months). With a median follow-up of 192 days, the median time to pain relief of 36 days and a median duration of response was not reached. Only 19% of patients required a second course of RT to a median dose of 20 Gy, echoing results from other studies in response-adapted radiotherapy in indolent lymphomas.1,2
Fast forwarding through the same album, Deshane et al. reported on a cohort of patients treated prospectively with 12 Gy in three fractions and compared with a historical cohort treated with a more common regimen of 20 Gy in five fractions. Seventy-one sites were treated in 50 patients. At the time of analysis, 37 patients treated to 50 sites had at least one follow-up PET scan after radiotherapy, resulting in an overall response rate (ORR) of 89% (47% complete response [CR]) and a local treatment failure rate of 14% after a median follow-up of 7.7 months. When compared to the historical cohort, the former included more extramedullary sites but were otherwise not significantly different in other dimensions. CR rates and ORR were not statistically different between the 12 Gy and 20 Gy cohorts.
Despite the known relative radiosensitivity of myeloma,3 many prior studies have lumped it together with other solid tumor histologies when evaluating various outcomes.4 Studies like those from Ballas et al. and Deshane et al. are leading the new wave, effectively chopping the need for extended, higher dose regimens commonly used for palliation of solid tumor metastases.
Changing tracks to solitary plasmacytoma, Laroze et al. took a novel approach, harmonizing definitive radiotherapy with concurrent lenalidomide. Presented by Youlia Kirova, MD, this retrospective analysis of a prospectively registered cohort compared 33 patients treated with combined modality therapy to 42 patients treated with radiotherapy alone. After a median dose of 40 Gy and with a median follow-up over six years, the overall cohort had expected outcomes, but the addition of lenalidomide was associated with a significant improvement in PFS (HR 0.315, p=0.012). Five-year and 10-year PFS estimates were 71.8% versus 49.1% and 71.8% versus 26.7%, respectively, with no grade ≥2 radiation-related toxicities.
At the crossroads between multiple myeloma and solitary plasmacytoma, winds of change may be blowing in the management of plasma cell neoplasms.
Abstract 10, Phase II Multi-Institutional Study of Ultralow-Dose (4Gy) Response-Adapted Radiotherapy for Symptomatic Bone Metastases from Multiple Myeloma, was presented during CT 01 – Clinical Trials Session, at ASTRO’s 68th Annual Meeting.
Abstract 1087, Fast Forward: Hypofractionated, Dose De-escalated Radiotherapy for Multiple Myeloma, and Abstract 1084, Solitary Plasmacytoma Treated by Lenalidomide and Dexamethasone in Combination with Radiation Therapy: Long Term Clinical Outcomes, were presented during QP-15 – Boston Heme Party: Bite-sized Breakthroughs, at ASTRO’s 68th Annual Meeting.
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Published on: September 28, 2026
