Statistics

Clinical characteristics including age, sex, percentage of the total resection of the contrast-enhanced tumor, use of gliadel wafer, isocitrate dehydrogenase-1 (IDH-1) mutation status, 6-O-methylguanine–deoxyribonucleic acid (DNA) methyltransferase (MGMT) methylation status, progression-free survival and overall survival were compared between the group with the q > CE and the group with the q ⩽ CE. Comparison of patients characteristics between these groups was calculated by paired t test for continuous data and by chi-square with Fisher’s exact test for small-number categorical data. Overall survival and progression-free survival between the groups were calculated by the Kaplan–Meier method with log-rank test. All statistics were analyzed using SPSS version 22 (IBM Inc. New York, U.S.). The statistical significance was defined by two-sided p value < 0.05.