IDH1 and astrocytoma (excluding glioblastoma): In addition, IDH-mutant astrocytomas have a more favourable prognosis compared to IDH-wildtype glioblastomas, even in high-grade cases, with grade 4 IDH-mutant astrocytomas having a median overall survival (OS) of 31 months, compared to IDH-wildtype glioblastomas with a median OS of 13 months [5,6].