Abstract 5956: Glioblastoma in Appalachia: A retrospective analysis

Introduction: Glioblastoma (GBM) is a fatal malignancy of the brain. It has been observed that patients in rural areas with GBM have worse overall survival. Higher morbidity and mortality in these rural areas have been attributed to lack of optimal access to clinical care and lack of participation in clinical trials. However, the projected number of cases and mortality risk related to GBM do not reflect the reality of Appalachian region. In this retrospective study, we reviewed the survival data of patients with GBM in Appalachia. Methods: 169 ( of 761) patients with grade 4 IDH WT GBM from 1/16/2019 through 7/1/2024 were selected for this retrospective study. Patient data, including demographics, insurance status, comorbidities, tumor location, diagnosis date, treatment regimens, treatment start dates, progression dates, MGMT methylation status, genetic mutations, and date of mortality, were extracted from electronic medical records and stored in RedCap in a HIPAA compliant manner. De-identified data was exported, organized and processed using Microsoft Excel Version 2409. Progression-free survival (PFS) and overall survival (OS) were calculated using standard Excel functions. A Cox proportional hazards model was employed to estimate the hazard ratios and corresponding p-values. Results: The median age of GBM diagnosis was 63.4 years. 91 patients were males and 78 were females. 164 patients were Non-Hispanic White. 96 patients with Medicaid, 53 had no insurance, and 11 had Medicare. The mean PFS was 22 months (mo) for the 1st line therapy (n=166), 12 mo for 2nd therapy (n=83), 10 mo for 3rd line therapy (n=28), and 16 mo for the targeted therapy (n=46). The mean OS was 22 mo for first-line therapy (n=61), 19 mo for first/second-line therapy (n=39), and 22 mo for 1st/2nd/targeted therapy (n=20). A significant association was found between RT-TMZ and increased mortality (95% CI 1.2-5.39, p=0.015) compared to RT-TMZ-surgery. In the 2nd line setting, no significant differences in PFS or OS were observed between bevacizumab+lomustine (n=7), bevacizumab+surgery (n=9), bevacizumab +temozolomide (n=8), and bevacizumab (n=41). In the 3rd line setting, a significant difference in PFS was observed between lomustine (95% CI 1.15-48.9, n=4) and bevacizumab (n=11), but not between bevacizumab and bevacizumab+lomustine (n=3). In the 2nd line targeted therapy setting, no significant differences in PFS or OS were observed between osimertinib (n=2), pembrolizumab (n=2), regorafenib (n=3), and abemaciclib (n=3). In the 3rd line targeted therapy setting, no significant differences in PFS or OS were observed between ipilimumab-nivolumab (n=3) and abemaciclib (n=2). Conclusion: Our preliminary data suggests that mortality related to GBM in Appalachia follows the national trends. It is prudent to conduct rural-specific studies to understand the phenotypic, genotypic, and demographic characteristics. Citation Format: Umer Rizwan, Gary Monroe, Sonikpreet Aulakh. Glioblastoma in Appalachia: A retrospective analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5956.