Article
Prognostic value of contrast enhancement and histopathological grading in diffuse glioma depends on IDH1/2 mutation
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Published: | June 9, 2017 |
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Outline
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Objective: Contrast enhancement (CE) and anaplasia have been reported to indicate poor outcome in diffuse glioma. Recently, mutational status of the IDH1/2 gene and co-deletion of on chromosome 1p/19q (co-del 1p/19q) have gained relevance for the evaluation of clinical outcome. Thus, we aimed at re-assessing the value of CE and histopathological grading within this framework of these molecular markers.
Methods: 332 patients with grade II (n=189) or grade III diffuse glioma (n=143) were stratified into 3 groups: IDH1/2 wild type (n=118), IDH1/2 mutated with (n=123) and without (n=91) co-del 1p/19q. Preoperative magnetic resonance (MR) imaging was reviewed and volumetrical analyses of CE and T2 volumes were performed. Univariate and multivariate analyses were conducted using molecular and imaging factors as well as age, Karnofsky performance status, surgical procedure and adjuvant therapy.
Results: In the multivariate analysis, histopathological grading had a strong independent prognostic value on OS in IDH1/2 wild type tumors (p=0.001). Conversely, CE is not associated with overall survival in IDH1/2 wild type tumors. In gliomas with IDH1/2 mutation, presence of CE is an independent prognostic factor for survival independently of its magnitude (p=0.04) while larger T2 volume is associated with shorter progression-free survival. This effect is especially pronounced in IDH1/2 mutated tumors without co-del 1p/19q.
Conclusion: In patients with diffuse IDH1/2 wildtype gliomas WHO grade II/III, CE is not associated with survival. In tumors with an IDH1/2 mutation, presence of CE on initial MRI is linked to inferior survival, but grading is not.