Outcomes and Prognostic Factors for Patients With Brainstem Metastases Undergoing Stereotactic Radiosurgery

Abstract

Abstract BACKGROUND: Treatment of tumors metastatic to the brainstem with stereotactic radiosurgery (SRS) has not been widely studied. OBJECTIVE: To identify the effects of SRS on patients with brainstem metastases by assessing duration of local progression-free survival (LPFS) and overall survival. METHODS: We retrospectively reviewed clinical data collected from 60 patients undergoing linear accelerator-based SRS for tumors metastatic to the brainstem between August 1994 and December 2007. The LPFS and overall survival were calculated with the Kaplan-Meier method. Prognostic factors were evaluated with the log-rank test and Cox proportional hazards model. RESULTS: The median age of patients was 61 years (range, 39-85 years); the median treated lesion volume was 1.0 mL (range, 0.1-8.7 mL); and the median SRS dose was 15 Gy (range, 8-18 Gy). The median overall survival interval after SRS was 4 months (95% confidence interval, 3.4-4.9 months); crude local tumor control was 76%; and median LPFS was 5.7 months (95% confidence interval, 3.0-8.4 months). Shorter overall survival was associated with a pretreatment tumor volume ≥4 mL (P < .001) and male sex (P = .03). Shorter LPFS was associated with a pretreatment tumor volume ≥4 mL (P = .008), a melanoma primary tumor (P = .002), and the presence of necrosis in pre-SRS magnetic resonance imaging (P = .04). A Basic Score for Brain Metastases of 2 to 3 vs 1 (P = .007) and a Score Index for Radiosurgery >5 (P = .003) were significantly associated with longer survival. Twelve patients (20%) developed SRS-related complications. CONCLUSION: Stereotactic radiosurgery provides noninvasive treatment and favorable local tumor control for patients with brainstem metastases.