Clinically, according to the depth of tumor invasion, it is divided into T1-T4 stages, T1 is the tumor invading the submucosal layer, T2 is the tumor invading the intrinsic muscularis propria, and T3 is the tumor penetrating the intrinsic muscularis propria to reach the subplasma layer or invading the paracolic tissues without peritoneal coverage. And T4 is divided into two: T4a is when the tumor penetrates the peritoneal visceral layer; while T4b is when the tumor directly invades or adheres to other organs or structures. So colon cancer invasion of nerves is not a basis for staging, but can only be considered as a risk factor for recurrence.