Speakers

Distinct molecular, imaging, and survival manifestations between molecular glioblastomas and histological glioblastomas
1109 14:20-14:30
AASNS & WANS Joint Seminar/305
Purpose Whether molecular glioblastomas (GBMs) identify with a similar dismal prognosis as a “classical” histological GBM is controversial. This study aimed to compare the clinical, molecular, imaging, surgical factors, and prognosis between molecular GBMs and histological GBMs. Methods Retrospective chart and imaging review was performed in 983 IDH-wildtype GBM patients (52 molecular GBMs and 931 histological GBMs) from a single institution between 2005 and 2023. Propensity score-matched analysis was additionally performed to adjust for differences in baseline variables between molecular GBMs and histological GBMs. Results Molecular GBM patients were substantially younger (58.1 vs 62.4, P = 0.014) with higher rate of TERTp mutation (84.6% vs 50.3%, P < 0.001) compared with histological GBMs. Imaging showed higher incidence of gliomatosis cerebri pattern (32.7% vs 9.2%, P < 0.001) in molecular GBMs compared with histological GBMs, which resulted in lesser extent of resection (P < 0.001) in these patients. The survival was significantly better in molecular GBM (median OS 30.2 months) compared to histological GBM (median OS 18.4 months, P = 0.001). The superior outcome was confirmed in propensity score analyses by matching histological GBM to molecular GBM (P < 0.001). Conclusion There are distinct clinical, molecular, and imaging differences between molecular GBMs and histological GBMs. Our results suggest that molecular GBMs have a more favorable prognosis than histological GBMs.

Revisiting gliomatosis cerebri in adult-type diffuse gliomas
1108 13:30-13:40
Neuro-oncology/305
Purpose: In adult-type diffuse gliomas, the gliomatosis cerebri (GC) is frequently neglected. We investigated the incidence, clinicopathologic and imaging correlates, and prognosis of gliomatosis cerebri in adult-type glioma patients reflecting the 2021 WHO classification. Methods: Between 2005 and 2021, there were 1,473 adult diffuse glioma patients, which was histologically confirmed in our institution. Among them, we excluded NOC or NEC, follow-up loss, and diffuse midline gliomas, H3 K27-altered cases. Finally, we included and analyzed 1,211 adult-type diffuse glioma patients. We re-classified the gliomas according to 2021 WHO classification based on pathologic and molecular data and reviewed the preoperative MRIs of all patients. Results: The incidence of GC was 8.2% in entire patients; 3.2% in oligodendroglioma, 7.8% in IDH-mutant astrocytoma, and 9.4% in IDH-wildtype astrocytoma including glioblastoma (p=0.017). In multivariable Cox analysis for overall survival, GC did not remain as an independent prognostic factor in whole group (p=0.083), but in IDH-wildtype astrocytomas including glioblastoma, remains as an independent prognostic factor (p=0.031). Conclusion: IDH-wildtype astrocytomas including glioblastoma manifest as GC more frequently, while oligodendrogliomas rarely manifest as GC. It may be explained by higher tumorigenecity and more infiltrative nature of IDH-wildtype gliomas. GC is an independent prognostic factor in IDH-wildtype astrocytomas and we should not neglect this finding.