T: primary tumor
TXPrimary tumor cannot be assessed
T0No evidence of primary tumor
T1Tumor invades lamina propria or submucosa and is 1 cm or less in greatest dimension
T2Tumor invades muscularis propria or is more than 1 cm in greatest dimension
T3Tumor invades subserosa (gastric NET) or pancreas / peripancreatic adipose tissue (duodenal NET)
T4Tumor perforates serosa or invades other adjacent structures
N: regional lymph nodes
NXRegional lymph nodes cannot be assessed
N0No regional lymph node metastasis
N1Regional lymph node metastasis
M: distant metastasis
M0No distant metastasis
M1aHepatic metastasis only
M1bExtrahepatic metastasis only
M1cHepatic and extrahepatic metastases