| Primary tumor (T) | |||
| T category | T criteria | ||
| TX | Primary tumor cannot be assessed | ||
| T1 | Tumor invades the mucosa or submucosa only and is ≤1 cm (duodenal tumors). Tumor ≤1 cm and confined within the sphincter of Oddi (ampullary tumors). | ||
| T2 | Tumor invades the muscularis propria or is >1 cm (duodenal). Tumor invades through sphincter into duodenal submucosa or muscularis propria, or is >1 cm (ampullary). | ||
| T3 | Tumor invades the pancreas or peripancreatic adipose tissue | ||
| T4 | Tumor invades the visceral peritoneum (serosa) or other organs | ||
NOTE: Multiple tumors should be designated as such (and the largest tumor should be used to assign the T category):
| |||
| Regional lymph nodes (N) | |||
| N category | N criteria | ||
| NX | Regional lymph nodes cannot be assessed | ||
| N0 | No regional lymph node involvement | ||
| N1 | Regional lymph node involvement | ||
| Distant metastasis (M) | |||
| M category | M criteria | ||
| M0 | No distant metastasis | ||
| M1 | Distant metastases | ||
| 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... |
| T1 | N0 | M0 | I |
| T2 | N0 | M0 | II |
| T3 | N0 | M0 | II |
| T4 | N0 | M0 | III |
| Any T | N1 | M0 | III |
| Any T | Any N | M1 | IV |
