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IDH Mutation – Prognostic Significance — SCE Neurology MCQ

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ModerateNeuro-oncologyIDH Mutation – Prognostic SignificanceSCE Neurology

A 50-year-old man with a recently diagnosed low-grade glioma (WHO grade 2 astrocytoma, IDH-mutant) asks about the significance of the IDH mutation. What is the prognostic significance?

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Correct answer: B — IDH-mutant gliomas have a significantly better prognosis than IDH-wildtype gliomas — median survival for IDH-mutant grade 2 astrocytoma is approximately 10–15 years compared with <2 years for IDH-wildtype GBM

IDH1/2 mutations are one of the most important prognostic markers in gliomas. IDH-mutant tumours have significantly better survival at every grade compared with IDH-wildtype tumours. IDH-mutant grade 2 astrocytomas have median survival ~10–15 years. IDH-wildtype diffuse astrocytomas are now classified as GBM (WHO 2021) regardless of histological grade, with a much worse prognosis (<2 years). The IDH mutation alters cellular metabolism (producing 2-hydroxyglutarate, which affects DNA methylation and gene expression). A: IDH status is the most important molecular prognostic marker. C: IDH mutation indicates better prognosis. D: IDH-mutant gliomas can still progress to higher grades. E: Both IDH and 1p/19q are important.

Reference: WHO CNS Classification (2021); NICE NG99