LGG-43. Reduction in the cerebrospinal fluid protein level after bevacizumab treatment in patients with optic pathway low-grade gliomas

Cases Presentations: Case 1: A 1-year-old boy with suprasellar pilocytic astrocytoma with previous history of shunting disfunction, treatment according vinblastine protocol due to anaphylactic reaction with carboplatin presented with ascites and necessity of ventricular-atrial shunt. Due to high protein cerebrospinal fluid (CSF) level (551mg/dl) he was submitted to external ventricular drainage and bevacizumab 10mg/kg was associated to his oncology treatment. After three cycles of bevacizumab, the patients’ CSF protein levels decreased dramatically 178 mg/dL, allowing the shunt procedure without complications and shorter hospital stay. Case 2: A ten-year-old boy with suprasellar pilocytic astrocytoma treated with three lines of chemotherapy showed tumor progression one year after the end of carboplatin-vincristine protocol and shunting disfunction. External ventricular drainage was performed, and the CSF showed 590mg/dl protein level. He was treated with vinblastine 6mg/m2 weekly and bevacizumab 10mg/kg each 14 days. After two cycles of bevacizumab, the protein level was 191mg/dl allowing another V-P shunt procedure. Discussion: Optic pathway gliomas frequently cause elevated cerebrospinal fluid protein concentrations leading to shunts occlusions and failures, necessity of external ventricular drainage and longtime hospitalization, implicating risk of serious infections. Bevacizumab is a monoclonal antibody with immunomodulatory and anti-vascular endothelial growth factor (VEGF) activities that has been used in combination with other chemotherapeutic agents such as irinotecan and vinblastine to treat low-grade gliomas and has been reported to decrease the CSF protein concentration.Final Comments: Bevacizumab treatment in patients with gliomas and high CSF protein levels seems effective in decreasing protein leakage from the vessels to the ventricles, thereby improving the scope for successful shunt placement.