PDCT-02. MARKED RECOVERY OF VISION IN A CHILD WITH OPTIC PATHWAY GLIOMA TREATED UPFRONT WITH BEVACIZUMAB AND VINBLASTINE

Abstract

Optic Pathway Gliomas (OPGs) are relatively rare and account for up to 5% of brain tumors in children. They are low grade neoplasms (WHO grade I‐II), can originate from any location along the visual system (nerve, chiasm, tract or radiation) and can be sporadic or associated with Neurofibromatosis‐ 1 (NF‐1). Visual complaints are the major presenting symptoms and include visual acquity (VA) / visual field (VF) defects, Nystagmus and Proptosis. Standard front line therapy (Vincristine/ Carboplatin) produces mild improvement in VA in one third of the patients. Bevacizumab, an antiangiogenic agent that targets vascular endothelial growth factor has been shown to help in recovery of vision in children with OPGs. We report a case of a sporadic Left optic pathway (nerve/chiasm) glioma treated upfront with Bevacizumab and Vinblastine resulting in significant and sustained recovery of vision. Our patient presented to us with a rapidly increasing lesion arising from the left intracranial optic nerve / chiasm with significant mass effect and peripheral contrast enhancement on serial follow up imaging (MRI). Ophthalmological exam revealed VA of 6/150 (was 6/12) and a 2+ afferent pupillary defect in the left eye. Biopsy of the lesion revealed Pilocytic astrocytoma (WHO Grade‐I) which was negative for BRAF (V600E mutation and fusion defects). He is being treated with Weekly IV Vinblastine (6mg/ m2) for a total of 68 weeks and IV Bevacizumab (10mg/kg) every two weeks for the initial 24 weeks. He has tolerated the treatment very well except for neutropenia (requiring dose reduction in Vinblastine). His visual assessment at 6months shows VA of 6/38 (left eye) and MRI shows > 50% reduction in the size of the lesion. Our case and case reports in literature suggesting recovery of vision in OPGs warrants incorporation of Bevacizumab in prospective randomized clinical trials for the treatment of chemotherapy naïve children with OPGs.