Main Session
Sep 29
PQA 03 - Central Nervous System, Professional Development/Medical Education

2573 - Long-Term Outcomes in IDH-Wildtype Gliomas with Historical WHO Grade 2 and 3 Histology

08:00am - 09:00am PT
Hall F
Screen: 14
POSTER

Presenter(s)

Patrick Carriere, MD, PhD Headshot
Patrick Carriere, MD, PhD - MD Anderson Cancer Center, Houston, TX

P. P. Carriere1, O. Haisraely2, A. Aaroe3, R. Lewis4, M. Bolden1, K. Ahmed5, T. A. Swanson1, T. Beckham1, C. Wang1, B. De1, S. Perni6, M. C. Tom2, J. Li6, S. L. McGovern2, M. F. F. McAleer6, A. J. Ghia6, C. Chung6, D. R. Grosshans1, C. Kamiya-Matsuoka3, and D. N. Yeboa1; 1Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 2Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 4Department of Information Technology, The University of Texas MD Anderson Cancer Center, Houston, TX, 5Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 6Department of Radiation Oncology, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX

Purpose/Objective(s): Most existing studies focus on outcomes of histological glioblastomas (GBM) or IDH-mutant lower-grade gliomas, leaving a gap in understanding IDH-wt gliomas that were historically classified as lower-grade (WHO grade 2 and 3). IDH-wt grade 2 and 3 astrocytomas, now reclassified as molecular GBM, have limited prognostic data, particularly in the context of historical versus contemporary treatment strategies, and represent an aggressive and relatively rare subset of diffuse gliomas. This study aims to describe long-term outcomes in a contemporary cohort of IDH-wt gliomas with grade 2 and 3 histological features and identify factors influencing survival outcomes.

Materials/Methods: Patients diagnosed with IDH-wt WHO grade 2 and 3 gliomas between 1996 and 2019 were identified using applied to all electronic health records as part of an institutional Context Engine Data Management System. IDH status was primarily determined via immunohistochemistry and patients with IDH-mutant gliomas or GBM were excluded. Clinical and treatment variables were extracted, including age, tumor characteristics, extent of resection, radiation dose, and chemotherapy administration. Overall survival (OS) was estimated using Kaplan-Meier analysis, and a multivariable Cox proportional hazards model was utilized to assess independent prognostic factors. This study was approved by our Institutional Review Board.

Results: 65 patients met the inclusion criteria. Median age was 51 years (range 16-76), with 48.4% male and median pre-operative Karnofsky Performance Status (KPS) was 80 (60-100). Gross total resection was achieved in 53.8%, subtotal resection in 27.6%, and biopsy in 18.4%. Median radiation dose was 57 Gy (range 50.4-59.4), with 34.4% receiving concurrent chemotherapy and 70.4% adjuvant Median follow-up for entire cohort was 42 months (range 8-215 months) and median OS was 38 months (95% CI: 28.5-47.6). Grade 2 gliomas demonstrated a median OS of 74 months, whereas grade 3 gliomas had a median OS of 35 months (p=0.031). On multivariable analysis, older age was the only significant predictor of increased mortality (HR=1.014, p=0.037). Grade, extent of resection, adjuvant radiation, KPS and adjuvant chemotherapy were not independently predictive of survival.

Conclusion: This study provides a descriptive analysis of long-term outcomes for patients with IDH-wt WHO grade 2 and 3 gliomas, which are now classified as molecular GBM. While some unadjusted analyses have suggested that molecular GBM may have similar outcomes to traditional histological GBM, our data suggests there may be longer term survivors with molecular GBM. Future research should include clinical trials for the specific subset populations and refined prognostic models to better predict outcomes in this unique glioma subtype.