Prospective pilot study of cesium-131 brachytherapy for rapidly proliferating glioblastomas

Radiation plays a central role in glioblastoma treatment. Logistics related to radiation planning an surgical recovery can necessitate delay in radiation delivery from the time of diagnosis. Unimpeded tumor growth occurs during this periode, and is associated with poor clinical outcome. GammaTile (GT) is a brachytherapy platform consisting of cesium-131 seeds embedded with an absorbable collagen matrix. A prospective pilot study at University of Minnesota Medical School (Minneapolis) evaluated GT for IDH-wild type glioblastoma that grew > 100% in volume during the 30 days between the time of initial diagnosis/surgery and the radiation planning MRI. These patients underwent re-resection followed by GT placement. There were no surgical complications. The median hospital stay was 2 days (range 1-5). There was no 30-day mortality and one 30-day readmission (hydrocephalus). With a median follow-up of 11.6 months, the median overall survival was 10.0 months among patients treated for recurrent glioblastoma and 11.5 months among patients treated for newly diagnosed glioblastoma. The authors conclude that these results suggest that GT offers favorable local control with acceptable safety among patients with rapidly proliferating glioblastoma.