Guideline 67 Annex 1

Management of colorectal cancer
Annex 1

TNM (TUMOUR, NODE, METASTASIS) STAGING

T	Primary Tumour
TX	Primary tumour cannot be assessed
T0	No evidence of primary tumour
Tis	Carcinoma in situ¹
T1	Tumour invades submucosa.
T2	Tumour invades muscularis propria.
T3	Tumour invades through the muscularis propria into the subserosa, or into the non- peritonealised pericolic or perirectal tissues.
T4	Tumour directly invades other organs or structures, and/or perforates visceral peritoneum.^{2, 3}
N	Regional Lymph Nodes
NX	Regional lymph nodes cannot be assessed (eg previously removed)
N0	No regional lymph node metastasis.
N1	Metastasis in 1 to 3 regional lymph nodes.
N2	Metastasis in 4 or more regional lymph nodes.
M	Distant Metastates
MX	Distant metastasis cannot be assessed
M0	No distant metastasis.
M1	Distant metastasis present.

DUKES’ STAGING

A	Limited to the submucosa
B1	Tumor invades into but not through the muscularis propria, no lymph node involvement
B2	Tumor invades through the muscularis propria, no lymph node involvement
B3	Tumor directly invades other organs or structures (added)
C1	Regional lymph nodes involved
C2	Metastases present in nodes at mesenteric artery ligature (apical nodes)
D	Distant spread

Tis includes cancer cells confined within the glandular basement membrane (intraepithelial) or lamina propria (intramucosal) with no extension through muscularis mucosae into the submucosa
Direct invasion in T4 includes invasion of other segments of the colorectum by way of the serosa, eg invasion of the sigmoid colon by a carcinoma of the caecum.
Tumour that is adherent to other organs or structures, macroscopically, is classified T4. However, if no tumour is present in the adhesion, microscopically, the classification should be pT3.