IDH2 and central nervous system cancer: The role of EOR on OS in grade 3 tumors was recently analyzed in a retrospective court of 246 patients, and it was shown that extended resection benefits only a portion of patients with WHO grade 3 IDH-mutant gliomas; in particular, stratifying for age, no survival benefit from total resection was found in patients with astrocytoma older than 45 years [41].