Surgery (colectomy) is the primary treatment for colorectal cancer. How much of your colon is removed and whether other therapies, such as radiation or chemotherapy, are an option for you depend on how far the cancer has penetrated into the wall of your bowel and whether it has spread to your lymph nodes or other parts of your body.
Your surgeon removes the part of your colon that contains the cancer, along with a margin of normal tissue to help ensure that no cancer is left behind. Nearby lymph nodes are usually also removed. 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 for the elimination of body wastes 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.
In cases of rare, inherited syndromes, such as familial adenomatous polyposis, you may need removal of your entire colon and rectum. Then, in a procedure known as ileal pouch-anal anastomosis, your surgeon will likely construct a pouch from the end of your small intestine that attaches directly to your anus. This allows you to expel waste normally, although you may have several watery bowel movements a day.
If you have colon surgery, side effects may include short-term pain and tenderness, and temporary constipation or diarrhea. If you have a colostomy, you may develop an irritation on the skin around the opening (stoma).
If your cancer is small, localized in a polyp and in a very early stage, your surgeon may be able to remove it during a colonoscopy. If the pathologist determines that the cancer in the polyp doesn't involve the base — where the polyp is attached to the bowel wall — then there is a good chance that the cancer has been completely eliminated. Some larger polyps may be removed using laparoscopic surgery. In this procedure, your surgeon performs the operation through several tiny incisions in your abdominal wall, using small instruments with attached cameras that display your colon on a video monitor. He or she may also take samples from the lymph nodes that drain the area where the cancer is located. Doctors have long believed that laparoscopic surgery allows for a quicker, less painful recovery than traditional "open" surgery.
If your cancer is advanced or your health poor, only a small portion of your colon or rectum may be removed. This isn't as effective as surgeries that remove more tissue, and doctors mainly do this to relieve blockages or bleeding.
Chemotherapy uses drugs to destroy cancer cells. Chemotherapy can be used to destroy cancer cells after surgery, control tumor growth or to relieve symptoms of colorectal cancer. Your doctor may recommend chemotherapy if your cancer has spread. In some cases, chemotherapy is used along with radiation therapy.
Possible side effects of chemotherapy include nausea and vomiting, mouth sores, fatigue, hair loss and diarrhea. If your doctor suggests aggressive treatment with multiple drugs, be sure you understand the side effects and risks as well as the potential benefits.
Radiation therapy uses X-rays to kill any cancer cells that might remain after surgery, to shrink large tumors before an operation so they can be removed more easily, or to relieve symptoms of colorectal cancer. Radiation is usually reserved for treatment of rectal cancer. The goal of therapy is to damage the tumor without harming the surrounding tissue. If your cancer has spread through the wall of the rectum, your doctor may recommend radiation treatments in combination with chemotherapy after surgery. This may help prevent cancer from reappearing in the same place. Side effects of radiation therapy may include diarrhea, rectal bleeding, fatigue, loss of appetite and nausea.
Staging helps determine how well you'll do and what treatments are most appropriate for you. In both cases, the size of your tumor isn't as important as how far your cancer has spread. People being treated for colorectal cancer have a five-year survival rate as high as 90 percent if treated in an early stage, before it has spread. When cancer has spread to lymph nodes or nearby organs, the survival rate drops to 65 percent or less. The stages are:
Follow-up care after treatment for colorectal cancer is extremely important. During your regular checkups, you may have a physical exam, screening tests such as colonoscopy, chest X-rays to see if the cancer has spread, computerized tomography scans of your abdomen to look for enlarged lymph nodes and to see if the cancer has spread, and blood tests.