Radiosurgery of brain metastases with the Gamma Knife

A total of 130 patients with metastatic brain tumors were treated with the Gamma Knife; 85 had multiple lesions. The marginal dose was 14-30 Gy for the initial 20 cases during the first 6 months. Thereafter, we increased the marginal dose to between 25 and 30 Gy for the last 110 cases. The follow-up period ranged from 1 to 49 months (mean 9 months). The recurrence rate fell from 20% for the early low-dose cases to 4.6% for the later 110 higher-dose cases (p = 0.043). Transient neurological deterioration developed in 7 cases (5.4%), and permanent neurological deficits were recognized in a further 6 cases (4.6%). The relatively high prescription dose of 25-30 Gy at the margin of brain metastases treated with the Gamma Knife resulted in an acceptably high control rate with a low rate of complications.