IDH1 and oligodendroglioma: Survival models based on WHO CNS5 diagnosis achieved much cruder stratification, only distinguishing glioblastoma, IDH-wildtype [hazard ratio (HR) of 3.00 (median survival 365 days, IQR 536 (160–696)] from all others: astrocytoma, IDH-mutant [HR 0.55, median survival 1778 days, IQR 1358 (1159–2518)], oligodendroglioma, IDH-mutant and 1p/19q codeleted [HR 0.43, median survival 2198 days, IQR 1735 (1528–3263)] and the other gliomas [HR 0.63, median survival 2195 days, IQR 2290 (1195–3485)] (Fig. 6 and Table 1).