Staging of Colon Cancer

If you have been diagnosed with colon cancer, your physician will discuss the stage of your cancer with you. The stage of your cancer will help determine what course of treatment is right for you. The most commonly used staging system is the American Joint Committee on Cancer (AJCC) system, which is also referred to as the TNM system. The TNM system defines the size of the primary colon cancer tumor (T), whether or not any lymph nodes (N) are affected, and if the colon cancer has metastasized (M) anywhere else in the body. All of these factors combined determine the stage of your cancer, ranging from Stage 0 (also called carcinoma in situ, in which the colon cancer is contained in the inner lining of the colon) to Stage IV (in which the colon cancer has spread beyond the colon and invaded other organs and tissues in the body).  

In some cases, the stage of a cancer cannot be determined until after surgery to remove the tumor. Surgical resection (in which part of the colon or rectum is removed) is the most common treatment for colon cancer and can eliminate the colon cancer in about half of all cases. Chemotherapy and radiation therapy are often needed as well. These two treatment options can be used either alone or in combination with surgery or each other.

The chart below details each of the colon cancer stages and its standard treatment. The size and location of a tumor help determine how it is treated.

  • Colon Cancer Stage 0
    The cancer is confined to the inner lining of the colon. Treatment: Local excision (removal of the tumor without cutting through the abdominal wall) for smaller tumors or surgical resection for larger colon cancer tumors.
  • Colon Cancer Stage I
    The cancer has grown through several layers of the colon but has not breached the colon wall. Treatment: Surgical resection of the colon.
  •  Colon Cancer Stage II
    The cancer has grown beyond the wall of the colon and may be invading nearby tissues, but it has not spread to lymph nodes. Treatment: Surgical resection, plus radiation if your doctor thinks recurrence is likely. Chemotherapy is possible as part of a clinical trial but is not standard treatment for this stage of colon cancer.
  •  Colon Cancer Stage III
    The cancer has spread to nearby lymph nodes but not to other parts of the body. Treatment: Surgical resection plus chemotherapy. Radiation may be required for large tumors that have spread into nearby tissues.
  • Colon Cancer Stage IV
    The cancer has spread to distant organs and tissues (for example, the lung or liver). Treatment: Surgery is palliative, intended to relieve blockage of the colon and other complications rather than cure the cancer. People in poor health may not be good candidates for surgery. Chemotherapy and radiation may also be used to relieve symptoms. Large or numerous metastases may be treated with freezing, microwave therapy or other methods.