Physicians use the results of diagnostic tests to determine the site of the cancer and to stage it—or tell how far it has spread. This helps determine the outlook for recovery and the best course of treatment. Patients should work together with their physician to choose among several treatment options that may be used alone or in combination, and to understand the risks and benefits of each.
Surgery is the primary treatment for colorectal cancer, particularly in the early stages. For cancers that have not spread, surgery alone may provide a cure. Depending on the location and stage of the cancer, chemotherapy or radiation therapy may be used before surgery to shrink the tumor, or after surgery to kill any remaining cancer cells. Colorectal surgery can be performed in different ways:
Chemotherapy (also called “chemo”) employs oral or injected drugs to kill cancer cells. These drugs enter the bloodstream and travel throughout the body, making the treatment useful for cancers that have spread to distant organs. For colorectal cancer, chemotherapy is typically used to shrink rectal tumors before surgery. After surgery chemo may increase the survival rate for patients with some stages of cancer. While it is not typically indicated for advanced or recurrent colorectal cancer, it can help relieve symptoms.
Because chemo kills some normal cells in addition to malignant ones, it can cause side effects that vary depending on the type of drug used. These include, but are not limited to, fatigue, nausea, vomiting, loss of appetite, hair loss, mouth sores, changes in menstrual cycle and infertility. It can also cause low white blood cell and platelet counts resulting in higher risk of infection and easy bruising/bleeding. Chemotherapy is often used concurrently with radiation therapy.
Researchers are learning more about the gene changes in cells that cause cancer, enabling them to develop new drugs that specifically target these changes. These drugs work differently than standard chemotherapy drugs, usually with less severe side effects. Man-made proteins called monoclonal antibodies have been approved for use, along with chemo, against colorectal cancer.
Radiation that kills or shrinks tumors may be used alone or in combination with other treatments. It is often used to shrink tumors before surgery, which may spare the anal sphincter and prevent the need for a colostomy. It is also used after surgery to kill any remaining cancer cells and reduce the chance of the cancer returning. For rectal cancer, radiation is usually given with chemotherapy. However, due to the sensitive nature of this area, unpleasant side effects of radiation therapy can include more frequent bowel movements, diarrhea, abdominal cramping, pressure or discomfort in the rectal area, more frequent urination, burning with urination, skin irritation, nausea and fatigue.
Brachytherapy With brachytherapy, radioactive seeds (pellets) are placed next to, or directly into, the cancer. The seeds give off small amounts of radiation over several weeks. This method is sometimes used in treating people with rectal cancer, particularly sick or older people who would not be able to withstand surgery. It carries small risks associated with seed migration within the body.
3-D Conformal External-Beam Radiation Therapy Three-dimensional conformal radiation therapy is an innovative high-technology radiation technique. Computer simulation produces an accurate image of a tumor and surrounding organs so that multiple radiation beams can be shaped exactly to the treatment area. These precisely focused beams allow nearby normal tissue to be spared.
Intensity Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) IMRT/IGRT are rapidly replacing traditional radiation therapy for treating certain cancers. These methods deliver higher radiation doses more precisely to cancerous tumors while avoiding healthy tissue. For colorectal cancer, this type of radiation therapy may prevent some unpleasant side effects. IMRT/IGRT can also potentially shorten the duration of therapy and enable physicians to treat some colorectal cancers for which traditional radiation therapy was not an option.