Multicenter phase 3 trial of surgery and tile-based radiation therapy versus surgery and stereotactic radiation for newly diagnosed brain metastases

Postoperative stereotactic radiation (SRT) is standard-of-care for resected brain metastases. Implantation of cesium-131 collagen tiles (tile-based radiation therapy; TBRT) initiates focal radiation immediately after resection, potentially offering therapeutic advantages. The phase 3 noninferiority Radiation One and Done Study, at 32 centers in the US, compared safety and efficacy of resection (R) + TBRT versus R + SRT among patients with newly diagnosed brain metastasis indicated for surgical resection. Patients were preoperatively randomized 1:1 to R + TBRT (n=115) or R + SRT (n=115). Any nonresected brain metastases received SRT postoperatively. Co-primary outcomes were time-to-surgical bed recurrence (SBR) and surgical bed recurrence-free survival (SB-RFS). Among the patients in the mITT population (103 R + TBRT; 101 R + SRT), the median follow-up was 12.9 months. The median time-toSBR was not reached in R + TBRT versus 17.4 months in R + SRT (HR 0.06; p=0.0070). Median SB-RFS was not reached with R + TBRT versus 10.9 months with R + SRT (HR 0.48; p=0.0021). Overall adverse events did not appear to differ (79.0% versus 80.7%). The authors conclude that among patients with newly diagnosed brain metastases requiring resection, R + TBRT compared with R + SRT significantly improved SBR and SB-RFS.