Neuroendocrine tumors of the gastro-entero-pancreatic system

Table 2 TNM staging for pancreatic NETs[13], foregut and midgut gastrointestinal carcinoids[14]

	Pancreatic NETs			Foregut and midgut gastrointestinal carcinoids
T-primary tumor
Tx	Primary tumor cannot be assessed			Primary tumor cannot be assessed
T0	No evidence of primary tumor			No evidence of primary tumor
T1	Tumor limited to the pancreas and size < 2 cm			Tumor invades mucosa or submucosa and size ≤ 1 cm
T2	Tumor limited to the pancreas and size 2-4 cm			Tumor invades muscularis propria and size > 1 cm
T3	Tumor limited to the pancreas and size > 4 cm or invading duodenum or bile duct			Tumor invades subserosa
T4	Tumor invading adjacent organs (stomach, spleen, colon, adrenal gland) or the wall of large vessels (celiac axis or superior mesenteric artery)			Tumor invades adjacent structures
	For any T, add (m) for multiple tumors			For any T, add (m) for multiple tumors
N-regional lymph nodes
Nx	Regional lymph nodes cannot be assessed			Regional lymph nodes cannot be assessed
N0	No regional lymph node metastases			No regional lymph node metastases
N1	Regional lymph node metastases			Regional lymph node metastases
M- distant metastases
Mx	Distant metastases cannot be assessed			Distant metastases cannot be assessed
M0	No distant metastases			No distant metastases
M1	Distant metastases			Distant metastases
Disease stage
I	T1	N0	M0	T1	N0	M0
IIa	T2	N0	M0	T2	N0	M0
IIb	T3	N0	M0	T3	N0	M0
IIIa	T4	N0	M0	T4	N0	M0
IIIb	Any T	N1	M0	Any T	N1	M0
IV	Any T	Any N	M1	Any T	Any N	M1

Criteria for carcinoids of the appendix and colon rectum differ only for the tumor size.