| Primary tumor (T) | |||
| T category | T criteria | ||
| TX | Primary tumor cannot be assessed | ||
| T0 | No evidence of primary tumor | ||
| T1* | Invades lamina propria or submucosa and less than or equal to 1 cm in size | ||
| T2* | Invades muscularis propria or greater than 1 cm in size | ||
| T3* | Invades through the muscularis propria into subserosal tissue without penetration of overlying serosa | ||
| T4* | Invades visceral peritoneum (serosal) or other organs or adjacent structures | ||
| * NOTE: For any T, add (m) for multiple tumors [TX(#) or TX(m), where X = 1 to 4, and # = number of primary tumors identified¶]; for multiple tumors with different T, use the highest. ¶ Example: If there are two primary tumors, only one of which invades through the muscularis propria into subserosal tissue without penetration of overlying serosa (jejunal or ileal), we define the primary tumor as either T3(2) or T3(m). | |||
| Regional lymph nodes (N) | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node metastasis has occurred | ||
| N1 | Regional lymph node metastasis less than 12 nodes | ||
| N2 | Large mesenteric masses (>2 cm) and/or extensive nodal deposits (12 or greater), especially those that encase the superior mesenteric vessels | ||
| Distant metastasis (M) | |||
| M category | M criteria | ||
| M0 | No distant metastasis | ||
| M1 | Distant metastasis | ||
| M1a | Metastasis confined to liver | ||
| M1b | Metastases in at least one extrahepatic site (eg, lung, ovary, nonregional lymph node, peritoneum, bone) | ||
| M1c | Both hepatic and extrahepatic metastases | ||
| Prognostic stage groups | |||
| When T is... | And N is... | And M is... | Then the stage group is... |
| TX, T0 | NX, N0, N1, N2 | M1 | IV |
| T1 | N0 | M0 | I |
| T1 | N1, N2 | M0 | III |
| T1 | NX, N0, N1, N2 | M1 | IV |
| T2 | N0 | M0 | II |
| T2 | N1, N2 | M0 | III |
| T2 | NX, N0, N1, N2 | M1 | IV |
| T3 | N0 | M0 | II |
| T3 | N1, N2 | M0 | III |
| T3 | NX, N0, N1, N2 | M1 | IV |
| T4 | N0 | M0 | III |
| T4 | N1, N2 | M0 | III |
| T4 | NX, N0, N1, N2 | M1 | IV |
| For multiple synchronous tumors, the highest T category should be used and the multiplicity or the number of tumors should be indicated in parenthesis: eg, T3(2) or T3(m). | |||
