Long-term outcomes for low-grade intracranial ganglioglioma: 30-year experience from the Mayo Clinic

Abstract

Gangliogliomas comprise less than 1% of all brain tumors and occur most often in children. Therefore, there are a limited number of patients and data involving the use or role of adjuvant therapy after subtotal resections (STRs) of gangliogliomas. The objective of this study was to examine and review the Mayo Clinic experience of 88 patients with gangliogliomas, their follow-up, risk of recurrence, and the role of radiation therapy after STR or only biopsy. Eighty-eight patients with gangliogliomas diagnosed between 1970 and 2007 were reviewed. Data on clinical outcomes and therapy received were analyzed. The Kaplan-Meier method was used to estimate progression-free survival (PFS) and overall survival. The median age at diagnosis was 19 years. The median potential follow-up as of June 2008 was 142 months (range 9-416 months). Fifteen-year overall survival was 94%, median PFS was 5.6 years, with a 10-year PFS rate of 37%. Progression-free survival was dramatically affected by extent of initial resection (p < 0.0001). This single-institution retrospective series of patients with gangliogliomas is unique given its large cohort size with a long follow-up duration, and confirms the excellent long-term survival rate in this group. The study also shows the importance of resection extent on likelihood of recurrence. Patients with gangliogliomas who undergo STR or biopsy alone have poor PFS. Radiation therapy may delay time to progression in patients with unresectable disease.