Treatment of colorectal carcinoids: A new paradigm

Table 1 TNM classification for endocrine tumors of colon and rectum[20]

TNM
T-primary tumor1
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
T1	Tumor invades mucosa or submucosa
	T1a size < 1 cm
	T1b size 1-2 cm
T2	Tumor invades muscularis propria or size > 2 cm
T3	Tumor invades subserosa/pericolic/perirectal fat
T4	Tumor directly invades other organs/structures and/or perforates visceral peritoneum
N-regional lymph nodes
NX	Regional lymph node status cannot be assessed
N0	No regional lymph node metastasis
N1	Regional lymph node metastasis
M-distant metastases
MX	Distant metastasis cannot be assessed
M0	No distant metastases
M1	Distant metastasis

¹For any T add (m) for multiple tumors.