KRAS and cancer: There were no significant differences in mean ages, tumor location, histological type, AJCC/UICC cancer stage, retrieved lymph node number, vascular invasion, perineural invasion, pre-operative serum CEA level, and post-operative serum CEA level between patients with wild-type KRAS and those with mutated KRAS. OS (42.54 vs. 37.41 months, P = 0.293) and DFS (18.38 vs. 16.43 months, P = 0.487) were not significantly different between patients with wild-type KRAS and those with mutated KRAS.