Prognostic factors for brain metastasis from lung cancer after gamma knife radiosurgery.

To determine the factors related to optimal treatment of brain metastasis from lung cancer by gamma knife radiosurgery, we investigated those influencing survival and local tumor control. We observed 156 patients with 315 such lesions treated by gamma knife radiosurgery (GKS). The factor that most affected survival was whether extracranial disease was controlled at the time of treatment. Patients with a high Karnofsky Performance Score (KPS) tended to survive longer. The local tumor control rate was higher with tumors less than 20 mm in diameter than larger lesions. Tumors treated with a high marginal dose (23 Gy < or =) were better controlled than those treated with a lower marginal dose. Control of extranial lesions, high KPS, small (< 20 mm) lesions, and high marginal dose (23 Gy < or =) were important factors in obtaining good results with GKS for brain metastasis from lung cancer.