Gamma-knife radiosurgery for brain metastasis of renal cell carcinoma: Results in 42 patients

Background: The present study provides data from clinical experience with gamma-knife radiosurgery (GK) in patients with brain metastasis from renal cell carcinoma (RCC) and shows the value of this less invasive treatment modality. Methods: Forty-two patients received GK. Twenty of the 42 cases had multiple brain metastases. Extracranial metastases were observed in the lung (38 cases), bone (12 cases), liver (9 cases), lymph node (5 cases) and skin (6 cases). Results: Neurological symptoms seen in 40 patients were rapidly improved after GK in 32 patients (80%). Magnetic resonance imaging (MRI) evaluation after GK in 32 patients showed the disappearance of brain tumor in 9 patients (28%). Complete response was obtained by GK in tumors up to 30 mm in diameter. Repeated GK for newly developed lesions was conducted in 11 patients. Extracranial tumor resection was conducted in 7 cases (lung: 3, skin: 2, liver: 1, adrenal: 1). Chemo-radiotherapy or immunotherapy was effective in 8 cases (lung: 5, liver: 2, bone: 1). The actual one-, two- and three-year survival rates were 44.9%, 16.8%, and 11.2%, respectively. The median survival time was 12.5 months. In univariate analysis, the patients with successfully treated extracranial metastases had significantly better prognosis. In multivariate analysis, the patients with Karnofsky performance scale (KPS) greater than or equal to 80%, who were treated by GK more than once and obtained complete response (CR) or partial response (PR) by GK, had significantly better prognosis. Conclusion: Gamma-knife radiosurgery for RCC is an effective non-invasive modality of treatment. It offers a high local control rate and an improved quality of life and survival rate.