Gamma Knife Radiosurgery for Brain Metastases of Non-Lung Cancer Origin: Focusing on Multiple Brain Lesions

We describe postradiosurgical treatment outcomes of our consecutive series of 456 patients (220 females, 236 males, mean age; 60.5 years, range 19-86 years) who underwent gamma knife (GK) treatment for brain metastases originating from non-lung cancers, focusing particularly on GK treatment for multiple lesions. The most common primary cancers were breast (122; 26.8%), followed by lower alimentary tract (105; 23.0%), uro-genital (100; 21.9%), upper alimentary tract (56; 12.3%), others (41; 9.0%) and unknown (32; 7.0%). Mean and median tumor numbers were 6 and 2, respectively, range 1-55. The mean and median survival times were 12.7 and 7.0 months after GK radiosurgery. Postradiosurgical survival rates were 52.7% at 6, 29.0% at 12, 19.1% at 18, 13.5% at 24, 6.5% at 36 and 5.0% at 60 months. Number of lesions, maximum and cumulative tumor volumes, non-symptomatic, well-controlled primary tumors, no non-brain metastatic lesions, Karnofsky performance status better than 80%, having prior surgery and having at least two procedures were significant predictive factors for survival. Although tumor number was demonstrated to have a significant impact on the duration of survival, approximately 85% of patients with brain metastases died of causes other than brain disease progression, regardless of tumor number.