[Application of "Gamma-knife" radiosurgery in treatment of intracranial metastases of extracranial malignant tumors].

Treatment of intracerebral metastases is one of the key problems in neurooncology. Modern methods of combined treatment do not significantly affect terms of survival. Quality of life during the whole period of treatment depends on selected tactics. We summarized our experience of treatment of 119 patients with cerebral metastases of extracranial tumors with "Gamma-knife" stereotactic radiosurgery (GKSRS) during 2005 and 2006 years. "Leksell Gamma-knife C" was used for treatment procedures. Primary tumor was located in lung in 35 cases, in breast in 32 cases. Renal cancer metastases were less common (15 cases) as well as skin melanoma (14), colon cancer (8) and other localizations (6 cases). Total amount of treated metastases was 628. Marginal doses ranged between 15 and 24 Gy. During followup 77 patients were examined 153 times by contrast-enhanced MRI every 3 months. Mean follow-up period was 194.6 days (6.5 months). In 68 cases (88.3%) GKSRS provided total tumor control of 446 irradiated lesions (92%). Median survival after GKSRS was 8.2 months. All patients were assessed using RPA prognostic criteria. The best prognosis for life ( > 1 year) was observed in RPA I class patients. Median survival in patients with initial Karnofsky performance level < 70% (RPA III class) did not exceed 3.5 months. Presence of circumscribed brain involvement (less than 10 foci) is associated with more favorable prognosis (median survival is increased to 9.4 months). In patients with disseminated brain involvement (more that 10 metastases) survival median was 3.8 months (p < 0.05). GKSRS is minimally invasive, safe and effective method for treatment of intracerebral metastases of all main histological types of extracranial tumors. Local tumor control is observed in 88% of patients. Life expectancy prognosis depends on activity of extracranial process, initial condition of patient by the moment of treatment and initial spread of metastatic brain involvement.