Treatment

Treatment depends mainly on the size, location, and extent of the tumour, and on the patient's general health. Patients are often treated by a team of specialists, which may include a gastroenterologist, surgeon, medical oncologist, and radiation oncologist. Several different types of treatment are used to treat colorectal cancer. Sometimes different treatments are combined.

Surgery to remove the tumour is the most common treatment for colorectal cancer. Generally, the surgeon removes the tumour along with part of the healthy colon or rectum and nearby lymph nodes. In most cases, the doctor is able to reconnect the healthy portions of the colon or rectum. When the surgeon cannot reconnect the healthy portions, a temporary or permanent colostomy is necessary. Colostomy, a surgical opening (stoma) through the wall of the abdomen into the colon, provides a new path for waste material to leave the body. After a colostomy, the patient wears a special bag to collect body waste. Some patients need a temporary colostomy to allow the lower colon or rectum to heal after surgery. About 15 percent of colorectal cancer patients require a permanent colostomy.

Chemotherapy is the use of anticancer drugs to kill cancer cells. Chemotherapy may be given to destroy any cancerous cells that may remain in the body after surgery, to control tumour growth, or to relieve symptoms of the disease. Chemotherapy is a systemic therapy, meaning that the drugs enter the bloodstream and travel through the body. Most anticancer drugs are given by injection directly into a vein (IV) or by means of a catheter, a thin tube that is placed into a large vein and remains there as long as it is needed. Some anticancer drugs are given in the form of a pill.

Radiation therapy, also called radiotherapy, involves the use of high-energy x-rays to kill cancer cells. Radiation therapy is a local therapy, meaning that it affects the cancer cells only in the treated area. Most often it is used in patients whose cancer is in the rectum. Doctors may use radiation therapy before surgery (to shrink a tumour so that it is easier to remove) or after surgery (to destroy any cancer cells that remain in the treated area). Radiation therapy is also used to relieve symptoms. The radiation may come from a machine (external radiation) or from an implant (a small container of radioactive material) placed directly into or near the tumour (internal radiation). Some patients have both kinds of radiation therapy.

Biological therapy, also called immunotherapy, uses the body's immune system to fight cancer. The immune system finds cancer cells in the body and works to destroy them. Biological therapies are used to repair, stimulate, or enhance the immune system's natural anticancer function. Biological therapy may be given after surgery, either alone or in combination with chemotherapy or radiation treatment. Most biological treatments are given by injection into a vein (IV).

Clinical trials (research studies) to evaluate new ways to treat cancer are an appropriate option for many patients with colorectal cancer. In some studies, all patients receive the new treatment. In others, doctors compare different therapies by giving the promising new treatment to one group of patients and the usual (standard) therapy to another group.