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.

Table 2 Grading proposal for neuroendocrine tumors of colon and rectum[20]

Grade	Mitotic count (10HPF)1	Ki-67 index (%)2
G1	< 2	≤ 2
G2	2-20	3-20
G3	> 20	> 20

¹10 HPF (High Power Field) = 2 mm², at least 40 fields (at 40 × magnification) evaluated in areas of highest mitotic density; ²MIB1 antibody; % of 2000 tumor cells in areas of highest nuclear labeling.

Table 3 CaRRS: carcinoid of the rectum risk stratification [15,16]

Points	Size (cm)	Depth	Lymphovascular invasion	Mitotic rate (HPF)
0	< 1	Mucosa/submucosa	No	< 2/50
1	1–1.9	Muscularis or deeper	Yes	≥ 2/50
2	≥ 2

CaRRS is obtained by adding points associated with each clinicopathological feature; Low risk: 0 points; Intermediate risk: 1-2 points; High risk:≥3 points.