Figure 1.

Classification of colorectal cancers (American Joint Commission on Cancer): Tis—carcinoma in situ: intraepithelial or invasion of lamina propria; T1—tumour invades submucosa; T2—tumour invades muscularis propria; T3—tumour invades through muscularis propria into subserosa or into nonperitonealized pericolic or perirectal tissues; T4—tumour penetrates the surface of the visceral peritoneum or tumour directly invades or is histologically adherent to other organs or structures; N0—no regional lymph node metastasis; N1—metastasis in one to three regional lymph nodes; N2—metastasis in four or more regional lymph nodes; M0—no distant metastasis; M1—distant metastasis.