Evaluation And Prognostic Fatcor Analysis Of Stereotactic Radiosurgery For Brain Matestases

Objective To determine the outcome for brain metastases patients treated with linac-based stereotactic radiosurgery(SRS) and evaluate the potential prognostic factors.Methods We reviewed 104 patients with 196 brain metastatic tumors treated with a linac-based SRS from 1999 to 2009, including 39 patients with solitary and 65 with multiple brain metastases; male 69, femal 35. Brainlab stereotactic systerm was applied for the treatment. The center dose was 24 Gy-30 Gy (median 26Gy) and margin dose was 16Gy-28Gy (median 16.5Gy). And the other therapy was given based on the patient's situation. The Cox proportional hazards regression with univariate and multivariate analysis was performed with SPSS 10.0 software.Results During the follow-up, the focus shrinked or disappeared in 88 (84.62%), kept stable in 10(9.62%) and increased in 6(5.76%). In this series of 104 patients, the follow-up time was range 1 to 102 months median10 months. The median survival was 12 months after SRS (95%CI10.28-16.15). The actuarial overall survival rate was 53.21% and24.53% at 1,2 years respectively. Univariate analysis showed that age, KPS score, time of metastatic tumor, volume and number of brain metastases, pathology type of lung cancer treatment modality for brain metastases had an effect on survival; Multivariate analysis showed that Karnofsky Score, time of brain metastasis and tumor volume had a significant positive effect on survival.Conclusion Stereotactic radiosurgery is an effective treatment modality for brain metastases. Multiple factors may affect survival of the patients. It showed that the KPS score, time of brain metastasis and tumor volume were significant prognostic factors.