CNSC-22. CANCER NEUROSCIENCE IN THE OR: ELECTROPHYSIOLOGIC INSIGHTS AT THE TIME OF BRAIN TUMOR RESECTION

Abstract

Abstract Pioneering works by Venkatesh and Venkataramani demonstrated that formation of functional neural-glial synapses fosters development and growth of glial neoplasms. Resultant peritumoral neural hyperexcitability associates with tumor progression, though limited in vivo human data have been evaluated to date. We sought to enrich our understanding of these mechanisms by obtaining thin film intraoperative micro-electrocorticography (µECoG) recordings from patients undergoing primary brain tumor resection. METHODS: Intraoperative µECoG data for 8 patients with low- (LGG) and high-grade glioma (HGG, WHO grades 3 and 4) of various tumor histology were included. Analyses excluded any operative behavioral or cognitive tasks and evaluated data prior to stimulation for language or motor mapping. Following low pass (< 200 Hz) and notch filtering at 60, 120, and 180 Hz for ambient electrical noise, bandpower was calculated using multitaper spectral analysis for low frequency (LF, < 1 Hz), delta (1-4 Hz), beta (12-30 Hz), gamma (30-80 Hz), and high gamma (80-200 Hz) bands. RESULTS: Compared to isocitrate dehydrogenase (IDH) wild-type tumors, those with IDH-mutation (n = 3; two WHO grade 3, one grade 4) demonstrated the highest proportion of power within the LF band (92.2% vs 71.4%) with relatively lower proportional beta (3.6% vs 18.3%) and gamma (2.2% vs 8.7%) bandpower. The same pattern was seen in HGG (n = 5) vs LGG (n = 3) tumors with higher LF (84.5% vs 70.3%) and lower beta (10.3% vs 16.8%) and gamma (3.5% vs 10.8%) bandpower, perhaps driven by three HGGs with IDH mutation. Absolute bandpower was highest at all bands in a patient with left frontal glioblastoma. CONCLUSIONS: Interesting patterns are emerging that corroborate differential high and low frequency neural activity among patients with primary brain tumors. Disparities in LF and beta/gamma bands may represent therapeutic targets or a non-invasive biomarker of disease activity but require further, ongoing data collection and analyses.