Gamma Knife radiosurgery for skull base metastasis and invasion.

We treated 18 patients with skull base metastasis or invasion using Gamma Knife radiosurgery. Seven of these patients had invasive nasopharyngeal cancer and 11 had distant metastasis from other cancers. The mean diameter of tumors was 22-46 mm (median 32.1 mm) and the radiation dose to the tumor margin was 12-23 Gy (median 16.2 Gy). The median follow-up period was 10.5 months. Clinical symptoms were improved in 61% of the patients after treatment and tumor control was obtained in 67% of cases at their final followup. Radiation injury occurred in only one patient (6%) who had received previous radiotherapy to the same region. Gamma Knife radiosurgery is a useful therapeutic option for the treatment of skull base metastasis and invasion, either as a secondary treatment for recurrence after previous radiotherapy or as a primary treatment.