Posted: Friday, November 11, 2022
At the 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 2799), researchers from The University of Texas MD Anderson Cancer Center, Houston, reported on outcomes of patients with extramedullary multiple myeloma who were treated with central nervous system (CNS)-directed radiotherapy. According to Gohar S. Manzar, MD, PhD, and colleagues, CNS-directed radiation appeared to be effective in certain patients, and an aggressive, multimodal therapy approach may permit durable control of CNS involvement.
“Extramedullary spread of multiple myeloma into the central nervous system is rare and confers a poor prognosis,” the investigators commented. “Outside of case reports, there is an undefined role of CNS-directed radiation therapy in managing [multiple myeloma with CNS involvement].”
The study retrospectively enrolled 16 patients. At diagnosis of multiple myeloma, seven patients (43.8%) had received three or more previous lines of therapy, seven cases (43.8%) had relapsed, and two cases (12.5%) were newly diagnosed. Separately, ten patients (62.5%) underwent craniospinal irradiation, four (25%) received brain radiotherapy, and two (12.5%) received spinal radiotherapy. Further, eight patients (50%) received intrathecal therapy with cytarabine following diagnosis of CNS involvement, and two patients (12.5%) underwent stem cell transplantation after irradiation.
Across all patients, the median overall survival was 46.6 months from myeloma diagnosis, 4.2 months after diagnosis of CNS involvement, and 3.9 months from the start of radiotherapy. Nine patients who had detailed follow-up consisting of cerebrospinal fluid analysis and MRI imaging were further evaluated. Among these individuals, the median overall survival from the start of radiotherapy was 7.2 months, with six patients (66.7%) achieving a complete response, two (22.2%) achieving a partial response, and one maintaining stable disease (11.1%). Of those who responded completely, two experienced a local relapse at 3 months and one patient, at 24 months following radiotherapy. The median overall survival in this subgroup was 7.3 months from the start of radiotherapy and 9.2 months from the diagnosis of CNS involvement.
Disclosure: Dr. Manzar reported no conflicts of interest.