Role of preoperative CT colonography in patients with colorectal cancer

Table 2 TNM staging of colorectal cancer¹

Stage	Description
Primary tumor (T)
T1	Tumor invades submucosa
T2	Tumor invades muscularis propria
T3	Tumor invades through the muscularis propria into the subserosa, or into the non-peritonealized pericolic tissues
T4	Tumor directly invades other organs or structures and/or perforates the visceral peritoneum
Regional lymph nodes (N)
N0	No regional lymph node metastases
N1	Metastases in 1-3 regional lymph nodes
N2	Metastases in ≥ 4 regional lymph nodes
Distant metastases (M)
M0	No distant metastases
M1	Distant metastases

¹American Joint Committee on Cancer (AJCC).