Outcome of Brain Metastases Treated with Gamma Knife Stereotactic Radiosurgery: A Retrospective Cohort Study of 205 Cases

Brain metastases (BMs) are the most common expansive intracranial lesions in adults. Approximately 50% of patients diagnosed with new BMs will have >1 BM at the diagnosis. We report our experience with BMs treated with Leksell Gamma Knife stereotactic radiosurgery (GKSR) and evaluate the outcomes. Patients treated by GKSR in our institution between 2008 and 2021 for BMs were evaluated retrospectively. A total of 205 patients (56.6% women) were included, with a median age of 59 years (range, 25–83 years). The breast (n = 85; 42.5%) and lung (n = 76; 38%) were the most common original locations for the primary tumors. Of the 205 patients, 103 (50.3%) had a single BM and 102 (49.7%) had ≥2 BMs. The median number of multiple BMs treated was 4 (range, 2–43). The mean overall survival (OS) time was 6.00 months (95% confidence interval [CI], 5.07–6.93 months) for all BMs. The median rate of tumor control after radiosurgery was 65% (range, 20%–99%) during a median follow-up of 6.00 months (95% CI, 3–84 months). In the overall population, the 1-, 2-, and 5-year OS rate was 37.55%, 25.12%, and 18.51%, respectively. The mean OS time was longer for those with multiple BMs than for those with a single BM (mean, 10 months [95% CI, 6.67–13.33 months] vs. mean, 5 months [95% CI, 4.21–5.70 months]; P = 0.03). Retreatment, tumor stability (control), and progression influenced the OS of patients with BMs, whether single or multiple (P < 0.001). GKSR provides good results in terms of OS and better quality of life for patients with BMs, whether single or multiple. Tumor stability and retreatment influenced the OS of patients with BMs.