The TNM staging system is currently used for the common international staging of colorectal cancer, which is based on the primary tumor (T), regional lymph nodes (N) and distant metastases (M). The traditional colorectal cancer staging also uses the Dukes’ staging system.
TNM staging system
Primary tumor (T)
Primary tumor cannot be evaluated
No evidence of primary tumor
Carcinoma in situ: confined to the epithelium or invading only the lamina propria of the mucosa
Tumor invades submucosal layer
Tumor invades intrinsic muscular layer
Tumor penetrating the lamina propria and invading the visceral layer of the peritoneum
Tumor penetrates the visceral peritoneal layer
Tumor directly invades or adheres to other organs or organs
Regional lymph nodes (N)
Regional lymph node status cannot be evaluated
No regional lymph node metastasis
1~3 regional lymph node metastases
1 regional lymph node metastasis
2~3 regional lymph node metastases
No regional lymph node metastasis with tumor implantation in the subplasma, mesentery, non-peritoneal covered colon, and perirectal tissues
4 or more regional lymph node metastases
4~6 regional lymph node metastases
7 and more regional lymph node metastases
Distant metastasis (M)
Distant metastasis cannot be evaluated
No distant metastasis
With distant metastasis
Distant metastases confined to a single organ or site (e.g., liver, lung, ovary, non-regional lymph nodes)
Distant metastases distributed to more than one organ/site or peritoneal metastases
Dukes’ staging system
Tumor does not penetrate the lamina propria
Tumor penetrates the lamina propria
Lymph node metastasis regardless of the extent of colon wall involvement