IDH1 and astrocytoma (excluding glioblastoma): When stratified by tumor type and by IDH mutation, there were significant survival differences between oligodendroglioma, IDH-mutant astrocytoma, and IDH-wildtype astrocytoma (Oligodendroglioma 1-year OS, 96% [89–100%] vs. IDH-mutant astrocytoma 1-year OS, 91% [81–100%] vs. IDH-wildtype astrocytoma 1-year OS, 63% [46–85%]; p < 0.001) (Figure 11).