For all but stage IV, surgery to remove the colon tumor is the primary or first treatment. Adjuvant therapy (additional treatments) may also be used.

Stage 0: Since your cancer has not grown beyond the inner lining of the colon, surgery to take out the cancer is all that is needed. This may be accomplished in many cases by polypectomy or local excision through the colonoscope. Colon resection may be necessary if your tumor is too big to be removed by local excision.

Stage I: Your cancer has grown through several layers of the colon. But it has not spread outside the colon wall itself. Surgical resection to remove the cancer is the standard treatment. You do not need any additional therapy.

Stage II: Your cancer has grown through the wall of the colon and may extend into nearby tissue. It has not yet spread to the lymph nodes. Surgical resection is usually the only treatment you need. If your doctor thinks your cancer is likely to come back because of its appearance under the microscope or because it was growing into other tissues, radiation or chemotherapy may be recommended. Radiation can be given to the local area of your abdomen where the cancer was growing. Chemotherapy is not standard treatment for this stage of colon cancer and should only be given as part of a clinical trial.

Stage III: This is a more advanced stage. Your cancer has spread to nearby lymph nodes. But, it has not yet spread to other parts of the body. Surgical resection is the first treatment. You should then receive chemotherapy with 5-FU and leucovorin. You may need radiation therapy if your cancer was also large enough to grow into adjacent tissues.

Stage IV: In this stage the cancer has spread to distant organs and tissues such as the liver, lung, peritoneum, or ovary. The goal of surgery (segmental resection or diverting colostomy) in this stage is usually to relieve or prevent blockage of the colon and to prevent other local complications. In some patients with extensive metastases, blockage can be prevented or managed by inserting a tube through the tumor (stent) during colonoscopy so that surgery can be avoided. If your cancer is small and your health poor, you might not have surgery.

Surgery in stage IV is usually not done with the expectation of curing the colon cancer. However, if only a few metastases (usually 5 or fewer) are present in the liver and can be completely removed along with the colon cancer, surgery can help you live longer and may even cure you. You would probably also be treated with chemotherapy directly into the arteries that lead into the liver.

Chemotherapy given in the arteries that lead into the liver shrinks the cancers in your liver more effectively than if the chemotherapy is given intravenously. The disadvantage of this treatment is that it permits the cancer to grow elsewhere in the body. Because of this, chemotherapy given into the liver for colon cancer usually does not usually prolong life any better than intravenous chemotherapy. But if there are only a few cancers in your liver and nowhere else, and the surgeon can remove them all, then giving chemotherapy into your liver may prolong your life or possibly even cure you. Some doctors will also give intravenous chemotherapy in this situation.

If metastases cannot be surgically removed because they are too large or there are too many of them, it may be possible to destroy the tumors by freezing, heating with microwaves, or other nonsurgical methods. Chemotherapy or radiation therapy (or both) may be given to relieve, delay, or prevent symptoms.

Recurrent colon cancer: Recurrent cancer means that your cancer has returned after treatment. The recurrence may be local (near the area of the initial tumor) or may affect distant organs. Surgery to remove local recurrences can sometimes help you live longer. As with stage IV colon cancer, surgery to remove metastases can also sometimes help you and, along with chemotherapy, can still be curative.

If your metastases can't be removed, chemotherapy is the main treatment. Drugs are selected based on which, if any, chemotherapy drugs you received before the cancer came back and how long ago you received them. You might want to consider a clinical trial.