A Mayo Clinic-led Phase 3 trial found that implanting cesium-131 collagen tiles during brain metastasis surgery cut one-year recurrence and was associated with longer overall survival compared with standard postoperative radiation. In the results, one-year surgical site recurrence dropped to 1.3% and median overall survival more than doubled in the tile arm. The trial also suggests that splitting postoperative radiosurgery into a localized, multi-session format can improve both local control and survival endpoints. For neurosurgical oncology, radioactive-tile implantation could become a distinct procedural alternative when balancing resection extent and postoperative radiation toxicity. The data elevate localized radiotherapy as a measurable survival strategy rather than a purely local control intervention.