Outcome of moderately dosed radiosurgery for limited brain metastases. Report of a single-center experience

Abstract

Purpose: Efficacy and safety of the own single-center experience with moderately dosed radiosurgery (SRS) for limited (one to four) brain metastases were analyzed and correlated with patient- and treatment-related variables.

Patients and methods: Between 05/1998 and 10/2006, 93 patients received SRS for a total of 142 brain metastases. The median number of brain metastases treated per patient was one (range, one to four). 46 patients (49%) received initial SRS alone, 13 patients (14%) SRS with up-front whole-brain radiotherapy (WBRT), and 34 patients (37%) SRS for recurrent metastases after WBRT. Median dose was 16 Gy (range, 10-20 Gy).

Results: Median overall survival (OS) was 7.5 months. The actuarial 6- and 12-month data for OS were 60% and 35%, for local brain control (LBC) 87% and 79%, and for distant brain control (DBC) 48% and 37%, respectively. Only ten of 46 patients (22%) with initial SRS alone ultimately received WBRT. Ten patients suffered from seizures within 3 months after SRS, six of them showed brain progression on magnetic resonance imaging (MRI). 20 patients required reinstitution of steroids following SRS, 16 of these due to brain progression. Five patients received positron emission tomography scan of the brain revealing radionecrosis in two patients. In uni- and multivariate analysis, only time interval between diagnosis of primary and brain metastases (p = 0.031) and volume of treated metastasis (p = 0.02) were significant predictors of OS. Neither up-front WBRT nor dose had a significant influence on LBC.

Conclusion: Moderately dosed SRS of limited brain metastases was found to be both effective and safe. Initial SRS only may be offered to informed patients complying with MRI-based follow-up.