Gamma Knife Radiosurgery for Brain Metastases in Patients Harboring Four or More Lesions: Survival and Prognostic Factors

ABSTRACT

OBJECTIVE: This study is performed to evaluate the role of gamma knife radiosurgery(GKS) for treatment of patients with large number of metastatic brain lesions. METHODS: The authors retrospectively reviewed the clinical outcome of 99 patients who underwent 124 GKS procedures for a total of 564 metastatic lesions. Sixty-three patients presented with 1 to 3 lesions (group A) and 36 patients presented with 4 or more lesions (group B) at initial GKS. The authors assessed survival according to a variety of possible prognostic factors. RESULTS: Median survival from the GKS for all cases was 28 weeks. The recursive partitioning analysis (RPA) class (p<0.0001) and the total tumor volume (p=0.0174) were significant factors influencing survival. The number of lesions, whole brain radiotherapy, primary tumor site, age, and sex were not significant. Median survival of group A (28 weeks) was not different from that of group B (28 weeks) (p=0.4027). Median survival was 66, 28, and 13 weeks for RPA class I, II, and III respectively in group A and 44, 36, and 11 weeks in group B. CONCLUSION: It is suggested that GKS provides a survival gain even in patients with a large number (4 or more) of metastatic lesions. Concerning the survival and the selection of patients for radiosurgery, RPA class and the total tumor volume should be considered as more important factors than the number of lesions. Multiplicity of the lesions alone should not be a factor for contraindication of radiosurgery.