Retrospective study of long-term outcomes of frameless stereotactic radiosurgery in the management of brain metastases

Gamma Knife radiosurgery (GKRS) for brain metastases has historically relied on pin-based frame fixation, with a frameless option introduced in recent years. A retrospective study at Columbia University Irving Medical Center (New York, NY) evaluated long-term oncologic and toxicity outcomes of single-fraction frameless GKRS. The study included 140 patients with a total of 362 brain metastases treated with frameless GKRS between 2018 and 2024. Primary tumor types included non-small cell lung cancer (32%), breast cancer (21%), melanoma (16%), and gastrointestinal cancer (9%). Median marginal dose was 20 Gy, with mean target volume of 0.14 cc. Median clinical follow-up time was 2.4 years. At 1- and 2-years post-treatment, local control was 98% (95% CI 96-100) and 97% (94-99), respectively. Median overall survival was 2.5 years (95% CI 1.99-4.27), One patient (0.7%) had symptomatich radiation necrosis following treatment. The authors conclude that frameless GKRS demonstrated excellent oncological outcomes.