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

Abstract

Purpose of Study: Glioblastoma multiforme (GBM) is themostmalignant primary tumor of the brain. It has a dismal survival prognosis of 14-16 months following initial diagnosis. Despite aggressive upfront therapy, GBM tumors tend to recur in six months. Following this recurrence, some patients may benefit from Gamma Knife Radiosurgery (GKRS) treatment. This study analyzes survival outcomes in a case series compared to known prognostic indicators for GBM patients. Methods Used: 63 patients with recurrent GBM 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 evaluated. Univariate and multivariate analyses were conducted to determine whether extent of resection, age, Karnofsky Performance Status (KPS), GKRS dose, or tumor volume were significant predictors of survival following GKRS salvage for recurrent GBM. Summary of 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. 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. Patients with KPS of 100 experienced 17.9 +/-5.5 month post-GKRS survival. Conclusions: GKRS may be a safe and effective salvage therapy for selected rGBM patients, providing prolonged survival and quality of life. Treatment options should be individually tailored to each patient's unique situation. (Table Presented) .