Case Series: Gamma Knife as Salvage Therapy for Recurrent Glioblastoma Multiforme

Abstract

Objectives: Glioblastoma multiforme is a highly malignant primary tumor of the brain. It has a dismal survival prognosis of 14-16 months following initial diagnosis. Despite aggressive upfront therapy, glioblastoma tends to recur in twelve months. Following this recurrence, some patients may benefit from Gamma Knife Radiosurgery (GKRS) treatment. This study analyzes survival outcomes in a case series by studying known prognostic indicators for glioblastoma patients.Methods: 63 patients with recurrent glioblastoma were treated with GKRS as part of a multimodal treatment plan between 2002 and 2011. Overall survival (from date of diagnosis) was compared to expected survival times as indicated by updated RTOG recursive partitioning analysis (RTOG-RPA) Classes. Survival post-GKRS salvage was also investigated. Univariate and multivariate analyses were conducted to determine whether there were significant predictors of overall survival for patients undergoing GKRS salvage. Results:Overall median survival from time of initial diagnosis was 20.2 ± 2.7 months for the entire group. 46 patients were in RTOG-RPA Class IV with a median overall survival of 20.2 ± 2.6 months (expected prognosis: 11.2 months). Median survival following GKRS salvage therapy was 9.9 ± 3.1 months for all patients. Multivariate analysis indicated that KPS was a significant predictor of survival (Hazard Ratio 0.22 compared to a KPS of 80).Conclusions: GKRS may be a safe and effective salvage therapy for selected recurrent glioblastoma patients, providing prolonged survival and quality of life compared to patients not receiving salvage treatment. Treatment options should be appropriately tailored to each patient's individual situation.