ED-32 * OUTCOMES OF PEDIATRIC BRAINSTEM LOW GRADE GLIOMAS: A SINGLE INSTITUTION SERIES

Abstract

BACKGROUND: Brainstem tumors constitute 10% of primary CNS tumor of children; 80% are malignant pontine gliomas, but 20% are low grade gliomas (LGG) with a more indolent course. Since advances in imaging & neurosurgical techniques, surgical resection is the initial treatment of choice for some of these tumors. However, optimal therapy for those which are incompletely resected or which relapse after surgery is uncertain. METHODS: We reviewed the clinical characteristics, therapy and outcomes of all children with non-tectal brainstem LGGs treated with surgical resection, chemotherapy (CT-carboplatin/VCR or thioguanine/procarbazine/CCNU/VCR), or radiation therapy (RT), at the University of Michigan Mott Children's Hospital over a 20 year period (1993-2013). RESULTS: Median age at diagnosis was 6 years; Histopathologic diagnosis was confirmed in 23/25 tumors; 61% were pilocytic astrocytoma, most often in cervicomedullary brainstem. Twenty one patients underwent initial tumor resection (11 GTR/NTR, 6 STR, 4 PR); 14 of these received no other therapy; 7 received adjuvant therapy (3-CT, 2-RT, 2 CT + RT) after surgery; 6 initially-resected tumors received CT at the time of local tumor relapse, to which all had partial or complete radiographic responses. Among 4 patients who underwent no initial surgical resection, 3 received RT at diagnosis, and 1 has stable disease, untreated for 2 years. All 25 patients are alive in remission with either stable disease or no evidence of disease, at a median follow-up of 12 years. Ten year relapse-free survival is 61 % and overall survival, 100%. DISCUSSION: This single institution retrospective study demonstrates excellent survival rates for children with brainstem LGG, with initial surgery +/- CT or RT, and effective salvage with CT. The efficacy of the well-tolerated chemotherapy in this series supports its role in the treatment of unresectable brainstem LGG, or in those which progress after initial surgical management.