T: primary tumor
TXPrimary tumor cannot be assessed
T0No evidence of primary tumor
TisCarcinoma in situ
T1aTumor limited to ampulla of Vater or sphincter of Oddi
T1bTumor invades beyond the sphincter of Oddi or into the duodenal submucosa
T2Tumor invades the muscularis propria of the duodenum
T3aTumor invades 5 mm or less into the pancreas
T3bTumor invades more than 5 mm into the pancreas or extends into peripancreatic tissue or duodenal serosa but without involvement of the celiac axis or the superior mesenteric artery
T4Tumor with vascular involvement of the superior mesenteric artery or celiac axis, or common hepatic artery
N: regional lymph nodes
NXRegional lymph nodes cannot be assessed
N0No regional lymph node metastasis
N1Metastasis in 1?2 regional lymph nodes
N2Metastasis in 3 or more regional lymph nodes
M: distant metastasis
M0No distant metastasis
M1Distant metastasis