Characteristics and long-term prognosis of patients with rectal neuroendocrine tumors

Table 1 Proposed tumor-node-metastasis classification for neuroendocrine tumors of the rectum (European Neuroendocrine Tumor Society 2007)[7]

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

TNM: Tumor-node-metastasis.

Table 2 Disease staging for neuroendocrine tumors of the colon and rectum[7]

Disease stage	T: Primary tumor	N: Regional nodes	M: Distant metastasis
Stage IA	T1a	N0	M0
Stage IB	T1b	N0	M0
Stage IIA	T2	N0	M0
Stage IIB	T3	N0	M0
Stage IIIA	T4	N0	M0
Stage IIIB	Any T	N1	M0
Stage IV	Any T	Any N	M1

Table 3 Comparison of 5-year survival rates in different age groups stratified by tumor type and tumor-node-metastasis stage

	≥ 55 yr of age		< 55 yr of age		P value
	n	Survival rate	n	Survival rate
Tumor type
Typical	20	95%	23	100%	0.284
Atypical	3	0%	2	100%	0.063
TNM stage
I/II	19	94.70%	23	100%	0.271
III/IV	4	25.00%	2	100%	0.144

TNM: Tumor-node-metastasis.