Table 1.
The 7th edition of the AJCC-TNM classification system.
| TNM | Disease extension |
|---|---|
| T1 | Tumour invades submucosa |
| T2 | Tumour invades muscularis propria |
| T3 | |
| a | Tumour invades through the muscularis propria |
| b | T1 or T2 tumour with satellite deposits in pericolorectal tissues |
| T4 | |
| a | Tumour penetrates the visceral peritoneum |
| b | Tumour directly invades or is adherent to other organs or structures |
| N0 | No regional lymph node metastasis |
| N1 | |
| a | Metastasis in 1 regional lymph node |
| b | Metastases in 2 to 3 regional lymph node |
| N2 | |
| a | Metastasis in 4 to 6 regional lymph nodes |
| b | Metastases in 7 or more regional lymph nodes |
| M0 | No distant metastases |
| M1 | |
| a | Metastasis confined to one organ or site (e.g., liver, lung, ovary, non-regional node) |
| b | Metastases in more than one organ/site or the peritoneum |
T, tumour stage; N, lymph node involvement; M, distant metastasis.