19 Age Related Presentation Characteristics and MRI Volumetric Associations in Glioblastoma IDHwt

Abstract Introduction Glioblastoma IDHwt is most common in adults aged ≥65 years, who often present with atypical symptoms, potentially impacting diagnostic pathways. We aimed to characterize presenting clinical features and MRI volumetric parameters in older adults with glioblastoma IDHwt at a single tertiary neurosurgical centre. Methods Clinical data were retrospectively collected for a continuous case series of patients diagnosed with glioblastoma IDHwt between 2020-2024 at Sheffield Teaching Hospitals Foundation Trust. Demographic and presenting features were analysed, particularly symptoms of raised intracranial pressure (ICP). For a subgroup of patients with left temporal lobe tumours, BrainLab annotation derived anatomical volumetric measures, with cerebrospinal fluid to total intracranial volume ratio (CSF:TIV) served as a surrogate for brain volume. Results 233 patients were included (median age 64 years, range 20–88), 151:82 male:female. Patients presenting with features of raised ICP were significantly younger than those without (median 55 vs 66 years; Welch’s t-test p < 0.001). When dichotomised at 65 years, patients with raised ICP were more likely to be aged ≤ 65 years (OR 0.30, 95% CI 0.14–0.63; Fisher’s exact p < 0.001). Within the subgroup with matched tumour locations, 16 diagnostic MRI scans were annotated (median age 56 years, range 33–86). Increased CSF:TIV demonstrated a moderate positive association with age (Spearman’s ρ = 0.43) and a moderate negative association with overall survival (Spearman’s ρ = −0.46); however, these findings lacked statistical significance. Conclusions These findings suggest age-related differences in presentation and intracranial volumetric profiles in glioblastoma IDHwt, with older adults being less likely to present with signs and symptoms of raised ICP, which may be associated with lower brain volumes. A multi-centre study is required to test this hypothesis in a larger cohort.