Staging of cancer colon

Generally, cancer of the large bowel is divided into four stages:

• Small and localised (stage A)
• Spread into surrounding structures (stages B and C)
• Or spread to other parts of the body (stage D).
  

TNM staging system

The Dukes system is gradually being replaced by the TNM staging system.

• T Describes the size of the tumour and if it has spread into the bowel wall.
• N Describes whether the cancer has spread to the lymph nodes.
• M Describes whether the cancer has spread to another part of the body, such as the liver or the lungs (secondary or metastatic cancer).

The Dukes staging system

• Dukes A The cancer is contained within the bowel wall.
• Dukes B The cancer has spread through the muscle of the bowel wall, but the lymph nodes are not affected.
• Dukes C The cancer has spread to one or more of the lymph nodes close to the bowel. Lymph nodes are usually the first place the cancer spreads to.
• Dukes D The cancer has spread to another part of the body such as the liver or the lungs (secondary cancer).

The stage system :

• Stage 0: The cancer is found only in the innermost lining of the colon or rectum. Carcinoma in situ is another name for Stage 0 colorectal cancer.
• Stage I: The tumor has grown into the inner wall of the colon or rectum. The tumor has not grown through the wall.
• Stage II: The tumor extends more deeply into or through the wall of the colon or rectum. It may have invaded nearby tissue, but cancer cells have not spread to the lymph nodes.
• Stage III: The cancer has spread to nearby lymph nodes, but not to other parts of the body.
• Stage IV: The cancer has spread to other parts of the body, such as the liver or lungs.
• Recurrence: This is cancer that has been treated and has returned after a period of time when the cancer could not be detected. The disease may return in the colon or rectum, or in another part of the body.