11500 Background: Stereotactic radiosurgery (SRS) has become a standard for the treatment of brain metastases. We attempted to determine if specific tumor- or patient-related factors in our population independently predicted better survival. Methods: Survival data for all 334 patients with brain metastases treated with SRS between Jan 1998 and Dec 2004 were analyzed. Clinical data were abstracted retrospectively from treatment records; survival data were obtained from the Connecticut Tumor Registry. Kaplan-Meier plots and Cox proportional hazard multivariate regression models were used to identify the factors that independently affected survival. Variables analyzed included age, sex, race, histology, number, location and total volume of metastatic lesions, surgical resection, WBXRT, chemotherapy, and systemic disease control. Results: Median age of our patient population was 57.3 years. The median number of lesions treated in a single session was 2 (range 1 to 36). Tumor histologies included non-small cell lung carcinoma (36%), breast (17%), melanoma (16%), small cell lung carcinoma (8%), renal cell (8%), esophageal (2%), and other (16%). Three hundred patients (90%) had confirmed deaths, with a median survival after SRS of 8.1 months. Increased survival was independently associated with systemic control (HR = 0.51, P<0.001), breast cancer (HR = 0.60, P=0.003), and total tumor volume <5cc (HR = 0.68, P=0.003). Decreased survival was independently associated with the presence of four or more cerebral metastases (HR = 1.50, P=0.005) and a trend toward decreased survival was associated with esophageal cancer (HR = 2.24, P=0.055). There was no difference in survival associated with age, race, sex, location of metastases, surgical resection, WBXRT before or after SRS, or chemotherapy. Conclusions: Breast cancer, systemic control, and fewer metastases were all significant independent predictors of improved survival. Of note, histological diagnosis, other than breast or esophageal cancer, did not affect patient survival, and a total tumor burden of 5cc or more was associated with worse survival independent of the number of metastases. These results should assist in survival prognostication in patients with cerebral metastases considering SRS. No significant financial relationships to disclose.