Colon and Rectum

TNM 7 classification

TNM 6 classification

1. Rules for Classification

The classification applies only to carcinomas. There should be histological confirmation of the disease.

The following are the procedures for assessing T, N, and M categories.

T categories. Physical examination, imaging, endoscopy, and/or surgical exploration
N categories. Physical examination, imaging, and/or surgical exploration
M categories. Physical examination, imaging, and/or surgical exploration

2. Anatomical Sites and Subsites

• Colon (C18)
  1. Appendix (C18.1)
     
  2. Caecum (C18.0)
     
  3. Ascending colon (C18.2)
     
  4. Hepatic flexure (C18.3)
     
  5. Transverse colon (C18.4)
     
  6. Splenic flexure (C18.5)
     
  7. Descending colon (C18.6)
     
  8. Sigmoid colon (C18.7)
     
• Rectosigmoid junction (C19)
• Rectum (C20)

3. Regional Lymph Nodes

For each anatomical site or subsite the following are regional nodes:

Appendix ileocolic Caecum ileocolic, right colic Ascending colon ileocolic, right colic, middle colic Hepatic flexure middle colic, right colic Transverse colon right colic, middle colic, left colic, inferior mesenteric Splenic flexure middle colic, left colic, inferior mesenteric Descending colon left colic, inferior mesenteric Sigmoid colon sigmoid, left colic, superior rectal (haemorrhoidal), inferior mesenteric and rectosigmoid Rectum superior, middle, and inferior rectal (haemorrhoidal), inferior mesenteric, internal iliac, mesorectal (paraproctal), lateral sacral, presacral, sacral promontory (Gerota)

Metastasis in nodes other than those listed above is classified as distant metastasis.

4. TNM Clinical Classification

4.1. T - Primary Tumour

TX. Primary tumour cannot be assessed
T0. No evidence of primary tumour
Tis. Carcinoma in situ: intraepithelial or invasion of lamina propria¹
T1. Tumour invades submucosa
T2. Tumour invades muscularis propria
T3. Tumour invades through muscularis propria into subserosa or into non-peritonealized pericolic or perirectal tissues
T4. Tumour directly invades other organs or structures^2,3 and/or perforates visceral peritoneum

4.2. N - Regional Lymph Nodes

NX. Regional lymph nodes cannot be assessed
N0. No regional lymph node metastasis
N1. Metastasis in 1 to 3 regional lymph nodes
N2. Metastasis in 4 or more regional lymph nodes

Note: A tumour nodule in the pericolic/perirectal adipose tissue without histological evidence of residual lymph node in the nodule is classified in the pN category as a regional lymph node metastasis if the nodule has the form and smooth contour of a lymph node. If the nodule has an irregular contour, it should be classified in the T category and also coded as V1 (microscopic venous invasion) or V2, if it was grossly evident, because there is a strong likelihood that it represents venous invasion.

4.3. M - Distant Metastasis

MX. Distant metastasis cannot be assessed
M0. No distant metastasis
M1. Distant metastasis

5. pTNM Pathological Classification

The pT, pN, and pM categories correspond to the T, N, and M categories.

pN0. Histological examination of a regional lymphadenectomy specimen will ordinarily include 12 or more lymph nodes. If the lymph nodes are negative, but the number ordinarily examined is not met, classify as pN0.

6. G Histopathological Grading

GX. Grade of differentiation cannot be assessed
G1. Well differentiated
G2. Moderately differentiated
G3. Poorly differentiated
G4. Undifferentiated

7. Stage Grouping

Stage 0 Tis N0 M0 Stage I T1, T2 N0 M0 Stage IIA T3 N0 M0 IIB T4 N0 M0 Stage IIIA T1, T2 N1 M0 IIIB T3, T4 N1 M0 IIIC Any T N2 M0 Stage IV Any T Any N M1

8. Summary

Colon and Rectum T1 Submucosa T2 Muscularis propria T3 Subserosa, non-peritonealized pericolic/perirectal tissues T4 Other organs or structures/visceral peritoneum N1 ≤3 regional N2 >3 regional

TNM 7 classification

TNM 6 classification