What Are the Treatments for Stage 4 Colon Cancer?

Colon cancer refers to cancer that originates in the colon. It often presents with rectal cancer and is called colorectal cancer. The most common type of colon cancer begins with an adenoma. In approximately 95 percent of cases, these adenomas (polyps) begin to grow in the lining of the colon and then spread to the center of the colon and/or the rectum. Colon cancer is usually slow growing, but when it becomes Stage IV, it is no longer curable because it has spread beyond the colon and rectum to distinct sites throughout the body.

Staging and Prognosis

• The staging of Colon Cancer uses the standard AJCC staging system pioneered by the American Joint Committee on Cancer. The staging system is also referred to as the TNM system because of the three factors used to determine the stage: the "T" factor, (for tumor size) the "N" factor (for lymph node involvement) and the "M" factor for metastasizes. Stage IV colon cancer has any T and N number, and an N number of 1, since the key distinguishing feature of Stage IV cancer is that metastases has occurred. The survival rates for Stage IV cancer are stated in terms of five-year survival, and according to the American Cancer Society, the survival rate for patients with Stage IV colon cancer is 8 percent. However, the University of Texas MD Anderson Center suggests that new treatments have increased the five-year survival rate to as much as 30 percent as of July 2009.

Treatment

• Stage IV colon cancer is not usually curable, although in rare instances surgery can cure the cancer if the metastasizes is local to a small spot in the liver or lungs. Chemotherapy, radiation and other treatments are used both to slow the spread of cancer and to improve quality of life for patients with Stage IV colon cancer.

Surgery

• Surgery is generally the most common treatment for Stage IV colon cancer. The surgery removes the primary tumor and cancer cells within the liver. Depending on the extent and location of metastasizes, surgery may also be performed to remove the cancer cells that have spread. For liver and lung metastases, surgery is possible and may remove the cancer at the site of metastases. The surgery performed on the liver is called cyrosurgery, and involves freezing the small portion of the liver that contains the cancer cells. In most cases, however, surgery is unlikely to cure the cancer, it only prolongs life and minimizes symptoms.

Chemotherapy

• Chemotherapy may be used to try to kill cancer cells both in the colon and in the area of metastases. The purpose of the chemotherapy may be to shrink the cancer cells in distant body parts where the metastases has occurred, to make them small enough to be removed for surgery. This type of chemotherapy, given prior to surgery, is called neo-adjuvant chemotherapy. Adjuvant chemotherapy may also be given after surgery to try to kill any remaining cancer cells. The most common chemotherapy agents used for Stage IV colon cancer are Folfox, Folfiri, CapeOx, bevacizumab and cetuximab. These chemotherapy agents may be used in conjunction with each other.

Other Treatments

• If the cancer is too widespread to attempt to cure, certain operations can be performed to reduce the symptoms and increase quality of life. A segmental resection or a colostomy can be used to remove blockages in the colon and restore bowel functions. A stent may also be inserted to keep the colon open. Finally, radiation therapy may be used to relieve symptoms or temporarily shrink tumors.