Imaging of gastroenteropancreatic neuroendocrine tumors

Table 2b Tumor node metastasis Staging (appendix, colon, rectum)

	Appendix	Colon/rectum
Tx	Primary Tumor cannot be assessed	Primary Tumor cannot be assessed
T0	No evidence of primary tumor	No evidence of primary tumor
T1	Tumor invades lamina propria or submucosa and </= 1 cm	Tumor invades mucosa or submucosa, T1a < 1 cm, T1b 1-2 cm
T2	Tumor invades submucosa, muscularis propria and/or minimally (up to 3 mm) invading subserosa/mesoappendix and </= 2 cm	Tumor invades muscularis propria or > 2 cm
T3	Tumor > 2 cm and/or invasion (more than 3 mm) of the serosa/ mesoappendix	Tumor invades subserosa/pericolic/perirectal fat
T4	Tumors invade peritoneum/other organs	Tumor directly invades other organs and/or perforates visceral peritoneum
Nx	Regional lymph nodes cannot be assessed	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis	No regional lymph node metastasis
N1	Regional lymph node metastasis	Regional lymph node metastasis
Mx	Distant metastasis cannot be assessed	Distant metastasis cannot be assessed
M0	No distant metastasis	No distant metastasis
M1	Distant metastasis	Distant metastasis