1238 Next Generation Sequencing of Gliomas to Identify Predictors of Time to Postoperative Epilepsy

Abstract

INTRODUCTION: Seizures during the course of disease for patients with diffuse gliomas is common. As genetic characterization of gliomas has improved, how a tumors mutational profile influences the timing of postoperative seizures, and if postoperative seizures relate to survival and tumor progression, is poorly understood. METHODS: A retrospective review of consecutive adults from 2017 to 2020 who underwent resection of gliomas with next generation sequencing of tumors at a single institution was performed. Cox proportional hazards regression was performed to identify factors associated with time to postoperative seizures. Seizures within 72 hours of surgery were excluded. RESULTS: 363 patients with newly diagnosed or recurrent tumor tissue genotyped via next generation sequencing were included. Median follow-up time was 37.4 months, median time to seizure after surgery was 39.2 months (95% CI 34.6 – 60.8), and IDH-mutant tumors comprised 38.3% of the cohort. Patients with IDH-mutant tumors were more likely to have non-immediate postoperative seizures (p = 0.031) and more persistent postoperative seizures (p = 0.004) compared to IDH-wildtype tumors. PDGFRA mutation was associated with shorter time to seizure in IDH-mutant gliomas (p = 0.033), with no such genetic factors in IDH-wildtype tumors. Among IDH-mutant and wildtype tumors, patients with shorter seizure freedom had significantly shorter overall and progression-free survival. CONCLUSIONS: PDGFRA mutation is associated with earlier seizures after resection of IDH-mutant diffuse gliomas. Earlier first non-immediate postoperative seizure after resection is associated with worse overall and progression-free survival.