MGMT and neoplasm: In the multivariable Cox regression analysis, the following factors were significantly associated with OS (Figure 2): age per year (hazard ratio (HR): 1.03, p < 0.001), STR versus biopsy only (HR: 0.15, p = 0.018), GTR versus biopsy only (HR: 0.13, p = 0.011), pRT versus no pRT (HR: 0.20, p < 0.001), postoperative TMZ‐based chemotherapy versus no postoperative chemotherapy (HR: 0.44, p = 0.003), MGMT promoter non‐methylated versus methylated (HR: 1.79, p = 0.05), and tumor diameter per cm (HR: 1.15, p = 0.046).