Gamma Knife surgery for brainstem metastases

Object. The goal of this study was to assess neuroimaging and clinical outcomes in patients harboring brainstem metastases that were treated with the Leksell Gamma Knife. Methods. Twenty-eight patients with brainstem metastases (32 lesions: 8 midbrain, 21 pontine, and 3 medullary) were consecutively treated with GKS. The primary cancer diagnoses in this group included 22 cases of lung cancer, 5 cases of breast cancer, and 1 case of rectal cancer. The median age of the patients was 61 years (range 45-83 years). The median treated lesion volume was 0.78 cm(3) (range 0.03-5.6 cm(3)), and the median GKS margin dose was 16 Gy (range 12-20 Gy). Overall survival in these patients was calculated using the Kaplan-Meier method. Results. The median survival time was 9 months after GKS (range 2-32 months). Survival was 39.3% at 1 year and 10.7% at 2 years. The tumor control rate in the series was 90.6% (29 of 32 lesions). Development of peritumoral edema occurred in 1 patient after GKS; 4 months after GKS, the edema disappeared. Conclusions. Gamma Knife surgery using a median margin dose of 16 Gy is a safe and effective local therapy for patients with brainstem metastases. (http://thejns.org/doi/abs/10.3171/2012.7.GKS121020)