The type of treatment given depends on the stage of cancer progression. More cancer is detected early in its evolution, the better the results.
Surgery is the main treatment. It involves removing the diseased portion of the colon or rectum, as well as some normal tissue around the tumor. If the tumor is at an early stage, for example at the stage of the polyp, it is possible to simply remove these polyps during a colonoscopy.
If the cancer has reached the rectum and a large portion of tissue has been removed, is practiced colostomy. This is to create a stoma through another opening made in the abdomen. Feces are then discharged into an adhesive pouch located outside the body.
Sometimes preventive surgery are practiced, in people at high risk of colorectal cancer.
Radiation and chemotherapy
These treatments are often necessary to kill cancer cells that have already migrated into the lymph nodes or elsewhere in the body. They are usually administered as adjuvant therapies, and are sometimes palliative treatment.
Radiation therapy uses various powerful ionizing radiation sources directed to the tumor. It is used before or after surgery, as appropriate. It can cause diarrhea, bleeding in the rectum, fatigue, loss of appetite and nausea.
Chemotherapy comprises administering, by injection or as tablets, for toxic chemical agents. It can cause several side effects, such as fatigue, nausea and hair loss.
Drugs which limit the proliferation of cancer cells are sometimes used, either alone or in addition to other treatments. Bevacizumab (Avastin®), for example, limit the growth of the tumor by preventing the formation of new blood vessels within the tumor. It is indicated when the cancer is metastatic.