Differences in the prognostic role of age, extent of resection and tumor grade between astrocytoma IDHmt and oligodendroglioma: a single center cohort study.

in Clinical cancer research : an official journal of the American Association for Cancer Research by Thijs van der Vaart, Maarten M J Wijnenga, Karin van Garderen, Hendrikus Jan Dubbink, Pim J French, Marion Smits, Clemens M F Dirven, Johan M Kros, Arnaud J P E Vincent, Martin J van den Bent

TLDR

  • The study looked at patients with a type of brain tumor called IDH-mutant glioma. They found that the size of the tumor after surgery is a good way to predict how long the patient will live. However, the study also found that other factors, like age and how aggressive the tumor is, are different for two types of IDH-mutant glioma called oligodendroglioma and astrocytoma. This means that researchers and doctors should treat these two types of tumors differently.

Abstract

IDH-mutant glioma are classified as oligodendroglioma or astrocytoma on the basis of 1p19q-codeletion. Whether prognostic factors are similar between these tumor types is not well understood. Retrospective cohort study. Molecular characterization was performed with targeted next-generation sequencing. Tumor volumes were calculated using semi-automatic 3D segmentation on all pre- and postoperative MRI-scans. Overall survival was assessed with Cox proportional hazards model. 383 patients with newly diagnosed IDH-mutant glioma were followed-up for a median of 7.2 years. Grade 3 and grade 4 patients had significantly lower Karnofsky performance, with tumors having more contrast-enhancement. Patients also received more aggressive post-surgery treatment. Postoperative tumor volume is significantly and independently associated with survival (HR per cm3 1.19, 95% CI 1.03 - 1.39) in IDH-mutant glioma. Separate analysis of oligodendroglioma and astrocytoma showed a significant association of postoperative tumor volume in astrocytoma, but not in oligodendroglioma. Higher age and histological tumor grade were associated with worse survival in patients with oligodendroglioma, but not with astrocytoma. Our data support an initial strategy of extensive resection in both oligodendroglioma and astrocytoma patients. Other important prognostic factors differ between these tumor types, urging researchers and clinicians to keep treating these tumors as separate entities.

Overview

  • The study aims to investigate the prognostic factors for IDH-mutant glioma, specifically comparing oligodendroglioma and astrocytoma subtypes. The study uses a retrospective cohort design and molecular characterization with targeted next-generation sequencing. Tumor volumes are calculated using semi-automatic 3D segmentation on all pre- and postoperative MRI-scans, and overall survival is assessed with Cox proportional hazards model. The study follows 383 patients with newly diagnosed IDH-mutant glioma for a median of 7.2 years. The primary objective is to identify prognostic factors for IDH-mutant glioma and their potential impact on treatment decisions.

Comparative Analysis & Findings

  • The study finds that postoperative tumor volume is significantly and independently associated with survival in IDH-mutant glioma (HR per cm3 1.19, 95% CI 1.03 - 1.39). Separate analysis of oligodendroglioma and astrocytoma subtypes shows a significant association of postoperative tumor volume in astrocytoma, but not in oligodendroglioma. Higher age and histological tumor grade are associated with worse survival in patients with oligodendroglioma, but not with astrocytoma. The study suggests that while postoperative tumor volume is a prognostic factor for both subtypes, other important prognostic factors differ between oligodendroglioma and astrocytoma, urging researchers and clinicians to keep treating these tumors as separate entities.

Implications and Future Directions

  • The study's findings highlight the importance of considering the subtype of IDH-mutant glioma when making treatment decisions. The study suggests that while postoperative tumor volume is a prognostic factor for both subtypes, other important prognostic factors differ between oligodendroglioma and astrocytoma. Future research should continue to explore these differences and develop personalized treatment strategies for each subtype. The study also highlights the need for more research on the molecular mechanisms underlying the differences between oligodendroglioma and astrocytoma subtypes.
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