Histologically proven, low-grade brainstem gliomas in children: 30-year experience with long-term follow-up at mayo clinic

Introduction: To evaluate long-term overall survival (OS), progression-free survival (PFS), and outcomes in pathologically proven brainstem low-grade gliomas (BS-LGG) in children. Methods: The Mayo Clinic tumor registry identified 48 consecutive children (≤20 y, 52% female) with biopsy-proven BS-LGG treated at Mayo Clinic between January 1971 and December 2004. Medical records were retrospectively reviewed. For analysis, patients were censored at the time of recurrence, death, or last follow-up. Results: The median age at diagnosis was 12 years with a median follow-up of 6.0 years. The majority of tumors were grade I (69%) and pathology was consistent with an astrocytoma in the majority of patients (98%). Gross total resection was obtained in 4, subtotal in 17, and 27 patients were biopsied only. Postoperative radiotherapy (RT) was used in 29 patients. Median OS for the entire group was 14.8 years with a 1-, 5-, and 10-year OS of 85%, 67% and 59%, respectively. Median PFS for the entire group was 7.3 years. Improved survival was associated with undergoing resection versus biopsy-only with 5-year OS rates of 85% and 50% (P=0.002), respectively. A high proportion of patients (42%) had diffuse tumors and 13 patients (27%) had diffuse pontine gliomas (DPGs). DPGs had an OS of 1.8 years with a worse median PFS than non-DPGs (1.8 vs. 11.1 y; P=0.009). RT was used preferentially in patients with poor prognosis such as those who had a biopsy-only procedure (19/27) and DPGs (9/13). Conclusion: OS in this single institution retrospective study in pathologically proven BS-LGG with extensive follow-up displayed favorable long-term outcomes. Improved outcomes were associated with nondiffuse classification.