RADT-16. ADJUVANT CHEMO-RADIATION THERAPY AS A RISK FACTOR FOR POSTOPERATIVE HYDROCEPHALUS FOLLOWING RESECTION OF HIGH-GRADE GLIOMA: A PROPENSITY-MATCHED CASE SERIES

Abstract The discovery of the neural glymphatic network in the past decade has significant implications for clinical investigations on hydrocephalus. With emerging understanding of how meningeal lymphatics and perivascular pathways impact cerebrospinal fluid dynamics, it is conceivable that inflammatory and fibrotic changes induced by radiation and chemotherapy may contribute to the pathogenesis of postoperative hydrocephalus, a well-documented sequela of resective neurosurgery. This study investigates differences in adjuvant chemo-radiation therapy patterns between patients who develop hydrocephalus following high-grade glioma resection and those who do not experience this postoperative complication. A retrospective chart review identified 328 adult patients who underwent tumor resection at our institution between 2010-2020, of which 257 had high-grade gliomas. Demographic and clinical data were collected, including resection history and adjuvant chemotherapy and radiation history. Propensity Score Matching generated comparative cohorts (n=27) using covariates sex, age at first surgery, surgery type, tumor location, extent of first resection, tumor-associated seizures, ventricular opening, number of additional resective surgeries, and pre-surgical Karnofsky Performance Scale score. Independent t-tests assessed differences in adjunctive chemo-radiation trends between patients who developed hydrocephalus within 3 years postoperatively and those who did not. 27 of 257 patients (10.5%) who underwent resection for high-grade glioma developed hydrocephalus within 3 years of their first surgery. Patients who developed hydrocephalus were more likely to have initiated the Stupp protocol(P=0.004), completed the Stupp protocol(P=0.02), and undertaken multiple cycles of the Stupp protocol(P=0.0004). Additionally, these patients had a smaller time window between surgery and adjuvant chemo-radiotherapy initiation than patients who did not develop hydrocephalus (P=0.02). Importantly, engagement in other clinical trial regimens with chemotherapy or radiation therapy did not differ significantly between groups(P=0.08, P=0.49, respectively). Shortened time to initiation of chemo-radiation therapy postoperatively and increased number of chemo-radiation cycles may increase a patient’s susceptibility to develop postoperative hydrocephalus following resection of high-grade glioma.