Gamma Knife Radiosurgery for Metastatic Brain Tumors-Study of 500 Cases with Cerebral Metastases from Major Primary Cancers

Abstract

The purpose of this retrospective study was to determine the outcome of gamma knife radiosurgery in a variety of patients including relatively poor-risk patients with multiple or large brain metastases.
Between April 2000 and March 2007, many patients with cerebral metastases from cancers of the lung, gastrointesinal tract, breast, and kidney were treated with gamma knife radiosurgery at Aizawa Hospital. Of the 500 patients who were suitable for analysis, there were 322 patients with lung cancer, 105 with gastrointestinal cancer, 48 with breast cancer, and 25 with renal cell carcinoma. A total of 728 treatment sessions were required for salvage therapy by June 2008 (the average was 1.5 times in one individual). The median followup period was 13.9 months. When the number of metastases was less than 10, the median survival after first gamma knife radiosurgery was 8.5 months in patients with lung cancer, 6 months with gastrointestinal cancer, 13 months with breast cancer, and 11 months with renal cell carcinoma. In a group of 284 patients with nonsmall cell lung cancer, the median survival was 13 months in patients with one metastasis, 11 months with 2 to 4 metastases, and 5 months with 5 to 10 metastases. There were 66 patients with metastases 3 to 4cm in diameter, and the median survival was 6 months. There were 10 patients who died from brain metastases (median survival was 16 months), and 8 patients in whom brain-tumor control had failed within 6 months after gamma knife radiosurgery.
The results of this study suggest that gamma knife radiosurgery may improve survival in poor-risk patients with multiple or large brain metastases even in palliative management.