| T: primary tumor | |
| TX | Primary tumor cannot be assessed |
| T0 | No evidence of primary tumor |
| Tis | Carcinoma in situ |
| T1a | Tumor invades lamina propria or muscularis mucosae |
| T1b | Tumor invades submucosa |
| T2 | Tumor invades muscularis propria |
| T3 | Tumor invades subserosa or non peritonealized perimuscular tissue |
| T4 | Tumor perforates visceral peritoneum or directly invades other adjacent structures (retroperitoneum, pancreas) |
| N: regional lymph nodes | |
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis in 1?2 regional lymph nodes |
| N2 | Metastasis in 3 or more regional lymph nodes |
| M: distant metastasis | |
| M0 | No distant metastasis |
| M1 | Distant metastasis |