Treatments and drugs

By Mayo Clinic Staff

The type of treatment your doctor recommends will depend largely on the stage of your cancer. The three primary treatment options are: surgery, chemotherapy and radiation.

Surgery for early-stage colon cancer

If your cancer is small, localized in a polyp and in a very early stage, your doctor may be able to remove it completely during a colonoscopy. Larger polyps may be removed using endoscopic mucosal resection. If the pathologist determines that it's likely that the cancer was completely removed, there may be no need for additional treatment.

Polyps that can't be removed during colonoscopy may be removed using laparoscopic surgery. In this procedure, your surgeon performs the operation through several small incisions in your abdominal wall, inserting instruments with attached cameras that display your colon on a video monitor. The surgeon may also take samples from lymph nodes in the area where the cancer is located.

Surgery for invasive colon cancer

If your colon cancer has grown into or through your colon, your surgeon may recommend a partial colectomy to remove the part of your colon that contains the cancer, along with a margin of normal tissue on either side of the cancer. Nearby lymph nodes are usually also removed and tested for cancer.

Your surgeon is often able to reconnect the healthy portions of your colon or rectum. But when that's not possible, for instance if the cancer is at the outlet of your rectum, you may need to have a permanent or temporary colostomy. This involves creating an opening in the wall of your abdomen from a portion of the remaining bowel for the elimination of body waste into a special bag. Sometimes the colostomy is only temporary, allowing your colon or rectum time to heal after surgery. In some cases, however, the colostomy may be permanent.

Surgery for advanced cancer

If your cancer is very advanced or your overall health very poor, your surgeon may recommend an operation to relieve a blockage of your colon or other conditions in order to improve your symptoms. This surgery isn't done to cure cancer, but instead to relieve signs and symptoms, such as bleeding and pain.

In specific cases where the cancer has spread only to the liver and if your overall health is otherwise good, your doctor may recommend surgery to remove the cancerous lesion from your liver. Chemotherapy may be used before or after this type of surgery. This treatment may improve your prognosis.

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells. Chemotherapy for colon cancer is usually given after surgery if the cancer has spread to the lymph nodes. In this way, chemotherapy may help reduce the risk of cancer recurrence.

Chemotherapy can also be given to relieve symptoms of colon cancer that has spread to other areas of the body. Chemotherapy may be used before surgery to shrink the cancer before an operation. In people with rectal cancer, chemotherapy is typically used along with radiation therapy.

Radiation therapy

Radiation therapy uses powerful energy sources, such as X-rays, to kill cancer cells that might remain after surgery, to shrink large tumors before an operation so that they can be removed more easily, or to relieve symptoms of colon cancer and rectal cancer.

Radiation therapy is rarely used in early-stage colon cancer, but is a routine part of treating rectal cancer, especially if the cancer has penetrated through the wall of the rectum or traveled to nearby lymph nodes. Radiation therapy, usually combined with chemotherapy, may be used after surgery to reduce the risk that the cancer may recur in the area of the rectum where it began.

Targeted drug therapy

Drugs that target specific defects that allow cancer cells to grow are available to people with advanced colon cancer, including bevacizumab (Avastin), cetuximab (Erbitux), panitumumab (Vectibix) and regorafenib (Stivarga). Targeted drugs can be given along with chemotherapy or alone. Targeted drugs are typically reserved for people with advanced colon cancer.

Some people are helped by targeted drugs, while others are not. Researchers are working to determine who is most likely to benefit from targeted drugs. Until then, doctors carefully weigh the limited benefit of targeted drugs against the risk of side effects and the expensive cost when deciding whether to use these treatments.

Aug. 22, 2013