The most common way of staging (describing the severity) of colorectal cancer is the American Joint Committee on Cancer’s TNM system. It includes information about the tumor, any involvement of lymph nodes and any metastasis (spread to other parts of the body). The stages for colorectal cancer are:

• Stage 0 (also called carcinoma in situ). Cancer is found in the innermost lining of the colon and/or rectum only.
  
  
• Stage I. Cancer has spread beyond the innermost lining of the colon and/or rectum to the second and third layers and involves the inside wall of the colon and/or rectum, but it has not spread to the outer wall or outside the colon and/or rectum.
  
  
• Stage II. Cancer has spread outside the colon and/or rectum to nearby tissue, but it has not gone into the lymph nodes.
  
  
• Stage III. Tumor cells have spread to lymph nodes near the colon/rectum.
  
  
• Stage IV colorectal cancer. Cancer may have spread to nearby lymph nodes and has spread to other parts of the body, such as the liver or lungs.

In addition there is recurrent colorectal cancer, when the disease returns after treatment. It may be treated with a combination of surgery, radiation therapy or chemotherapy.

Survival rates vary greatly depending on the stage in which colorectal cancer is diagnosed and treated. Cancer that is detected in the early stages before it has spread in the body has a better survival rate. According to the American Cancer Society, the five-year survival rate for colorectal cancer by stage is as follows: