Version July 2025
| Primary tumor (T)* | |||
| T category | T criteria | ||
| TX | Primary tumor cannot be assessed | ||
| T0 | No evidence of primary tumor | ||
| T1 | Tumor ≤2 cm in greatest dimension | ||
| T2 | Tumor >2 cm but ≤4 cm in greatest dimension | ||
| T3 | Tumor >4 cm in greatest dimension, or with subserosal invasion, or involvement of the mesoappendix | ||
| T4 | Tumor perforates the peritoneum, or directly invades other adjacent organs or structures (excluding direct mural extension to adjacent subserosa of adjacent bowel), eg, abdominal wall and skeletal muscle | ||
NOTE: Multiple tumors should be designated as such (the largest tumor should be used to assign T category):
Primary tumor suffix
| |||
| Regional lymph nodes (N)* | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No tumor involvement of regional lymph node(s) | ||
| N1 | Tumor involvement of regional lymph node(s) | ||
Regional lymph nodes suffix
| |||
| Distant metastasis (M)* | |||
| M category | M criteria | ||
| cM0 | No distant metastasis | ||
| cM1 | Distant metastasis | ||
| cM1a | Metastasis confined to liver | ||
| cM1b | Metastases in at least one extrahepatic site (eg, lung, ovary, nonregional lymph node, peritoneum, bone) | ||
| cM1c | Both hepatic and extrahepatic metastases | ||
| pM1 | Microscopic confirmation of distant metastasis | ||
| pM1a | Microscopic confirmation of metastasis confined to liver | ||
| pM1b | Microscopic confirmation of metastases in at least one extrahepatic site (eg, lung, ovary, nonregional lymph node, peritoneum, bone) | ||
| pM1c | Microscopic confirmation of both hepatic and extrahepatic metastases | ||
| AJCC prognostic stage group is assigned based on the stage classification and categories chosen.* | |||
| Prognostic stage groups | |||
| When T is... | And N is... | And M is... | Then the stage group is... |
| T1 | NX, N0 | M0 | I |
| T2 | NX, N0 | M0 | II |
| T3 | N0 | M0 | II |
| T4 | N0 | M0 | III |
| Any T | N1 | M0 | III |
| Any T | Any N | M1 | IV |
AJCC: American Joint Committee on Cancer; TNM: tumor, node, metastasis.
* AJCC data elements required for staging are identified with an asterisk.
