Staging of colorectal cancer

TNM classification of colorectal cancer

T Primary tumor
Tx Primary tumor cannot be assessed
T0 No evidence of primary tumor
Tis Carcinoma in situ: invasion up to lamina propria mucosae
T1 Tumor invades submucosa
T2 Tumor invades muscularis propria
T3 Tumor invades into pericolic tissue
T4a Tumor penetrates visceral peritoneum
T4b Tumor invades od adheres to other organs or structures


N Regional lymp nodes
Nx Regional lymph nodes cannot be assessed
N0 No regional lymph node involvement
N1 Metastasis in 1 - 3 regional lymph nodes
- N1a Metastasis in 1 regional lymph node
- N1b Metastasis in 2 - 3 regional lymph nodes
- N1c Tumor deposits in subserosa, mesentery or non-peritonealized pericolic or perirectal tissues with no regional lymph node metastasis
N2 Metastasis in ≥4 regional lymph nodes
- N2a Metastasis in 4 - 6 regional lymph nodes
- N2b Metastasis in >=7 regional lymph nodes


M Distant metastasis
M0 No distant metastasis
M1 Distant metastasis
- M1a Metastasis in one organ or site
- M1b Metastasis in more than one organ or site or the peritoneum

Staging of colorectal cancer

Stage T N M
Stage 0 Tis N0 M0
Stage I T1-2 N0 M0
Stage II IIa: T3
IIb: T4a
IIc: T4b
N0 M0
Stage III IIIa: T1-2
IIIb: T3-4
IIIc: T3-4b
Stage IV any T any N M1



1. How is colorectal cancer staged?
2. Colon and Rectum Cancer Staging.

3. AJCC Cancer Staging Manual, Edge SB, Byrd DR, Compton CC, et al., Springer, New York 2010