Kidney cancer with brain metastases. Prognostic factors and treatment outcome.

The aim of this study was to study the effectiveness of stereotactic radiosurgery by Gamma Knife in kidney cancer with brain metastases. There were analyzed results in 112 patients with such spread of the disease who received treatment in the Gamma Knife Center, Moscow. The median age of patients was 58 years (range, 33-77 years). Total number of metastatic lesions was 444, and the average number of brain metastases in one patient 4 (from 1 to 30). A single brain metastasis had 28 patients (25 %). Median of total volume of brain metastasis for each patient was 5. 9 cm3 (from 0. 1 to 29,1sm3). Mean marginal dose for metastatic lesion was 22 Gy (from 12 Gy to 26 Gy) and the average value of isodose, on which planning was performed - 64% (from 39% to 99%). The overall survival after radiosurgery was 37,7%, 16,4% and 9,3% for 12, 24 and 36 months, respectively, with a median overall survival of 9,1 months (95% CI = 7,1-11,8). New brain metastases after radiosurgical treatment occurred in 44 (54,3%) patients with a median of 10,1 months. (95% CI = 7-18). Local recurrences after radiosurgical treatment were detected in 19 (17%) patients with a median of 6,6 months (95% CI = 4,0-9,6). The Karnovsky index was >80. Local control was achieved in 96% of metastatic lesions in 87% of patients. Side effects of radiosurgical treatment occurred in 33. 8% of patients (6% radionecrosis and 23. 8% an increase of perifocal edema). Thus stereotactic radiosurgery by Gamma Knife is an effective treatment option for brain metastases in kidney cancer providing a high level of local control of metastatic lesions with minimal neurotoxicity. In a case of distant recurrence reuse of such treatment provides good local control and improves overall survival compared with other methods of treatment.