ESTRO 2024 - Abstract Book

S863

Clinical - CNS

ESTRO 2024

Felix Ehret 1 , Oliver Zühlke 1 , Leonille Schweizer 2 , Christoph Csapo-Schmidt 3 , Johannes Kahn 4 , Siyer Roohani 1 , Daniel Zips 1 , david capper 2 , sebastian adeberg 5 , Maximilian Knoll 6 , david kaul 1 1 Charité-Universitätsmedizin Berlin, Dept. of Radiation Oncology, Berlin, Germany. 2 Charité-Universitätsmedizin Berlin, Dept. of Neuropathology, Berlin, Germany. 3 Charité-Universitätsmedizin Berlin, Dept. of Radiology, Berlin, Germany. 4 HMU Potsdam, Dept. of Radiology, Berlin, Germany. 5 Universität Marburg, Dept. of Radiation Oncology, Marburg, Germany. 6 DKFZ Heidelberg, Dept. of Radiation Oncology, Heidelberg, Germany

Purpose/Objective:

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. GBM may originate from self renewing tumorigenic cancer stem cells (CSC) that rely on signals from their cellular milieu to maintain stem cell properties. The subventricular zone (SVZ) is the most abundant location for neuronal stem cells (NSC) lining the lateral ventricles and is actively involved in neurogenesis. GBM with contact to the SVZ might show a distinct molecular signature as they are closely related to a stem cell rich zone that can also harbor GBM stem cells.

Material/Methods:

We performed methylation analysis on formalin fixed paraffin embedded tissue blocks from 65 IDH-WT GBM patients treated at our institution. Preoperative MRI was independently reviewed by three experienced readers, two neuroradiologists and one radiation oncologist, who assessed GBM SVZ contact. Using Barnard’s test for 2x2 contingency tables, we compared the molecular SVZM signature with our consensual T1ce SVZ assessment. Overall survival (OS) vs. SVZ classification was estimated by Cox proportional hazards modeling from date of surgery to date of death or study end.

Results:

Barnard test indicated a strong association between MRI-based SVZ assessment and SVZM, but OS difference between SVZ+ and SVZ- was significant while difference between SVZM+ and SVZM- failed to reach significance and was smaller than between SVZ+ and SVZ-. However, small sample size precluded a conclusive determination.

Conclusion:

Whether SVZM can replace SVZ as a prognostic tool will require prospective studies with larger patient samples.

Keywords: Glioblastoma

1864

Digital Poster