Definition of Primary Tumor (T), Regional Lymph Node (N), and Distant Metastasis (M) Categories for Ampullary Adenocarcinoma according to the Eighth Edition American Joint Committee on Cancer Staging System
| Category | Criteria | |
|---|---|---|
| T category | T0 | No evidence of primary tumor |
| Tis | Carcinoma |
|
| T1 | Tumor limited to ampulla of Vater or sphincter of Oddi or tumor invades beyond the sphincter of Oddi (perisphincteric invasion) and/or into the duodenal submucosa | |
| T1a | Tumor limited to ampulla of Vater or sphincter of Oddi | |
| T1b | Tumor invades beyond the sphincter of Oddi (perisphincteric invasion) and/or into the duodenal submucosa | |
| T2 | Tumor invades into the muscularis propria of the duodenum | |
| T3 | Tumor directly invades the pancreas (up to 0.5 cm) or tumor extends more than 0.5 cm into the pancreas, or extends into peripancreatic or periduodenal tissue or duodenal serosa without involvement of the celiac axis or superior mesenteric artery | |
| T3a | Tumor directly invades pancreas (up to 0.5 cm) | |
| T3b | Tumor extends more than 0.5 cm into the pancreas, or extends into peripancreatic tissue or duodenal serosa without involvement of the celiac axis or superior mesenteric artery | |
| T4 | Tumor involves the celiac axis, superior mesenteric artery, and/or common hepatic artery, irrespective of size | |
| N category | N0 | No regional lymph node metastasis |
| N1 | Metastasis to one to three regional lymph nodes | |
| N2 | Metastasis to four or more regional lymph nodes | |
| M category | M0 | No distant metastasis |
| M1 | Distant metastasis |