IDH1 and oligodendroglioma: Concerning the patients characteristics and treatments there were no major differences between WHO grade II and III subgroups in median age (astrocytoma 37/37 years; IDH1-R132H-nm 50/55 years; oligodendroglioma 44/48 years) but grade III tumors were treated more frequently with RT or RCT during first-line therapy (astrocytoma 21/70%; IDH1-R132H-nm 32/74%; oligodendroglioma 24/60%).