The choice of treatment depends mainly on the location of the tumor in the colon or rectum and the stage of the disease. Treatment for colorectal cancer may involve surgery, chemotherapy, biologic therapy or radiation therapy. Some people have a combination of treatments. These treatments are described below.
Colon cancer sometimes is treated differently from rectal cancer. Treatments for colon and rectal cancer are described separately below.
Your doctor can describe your treatment choices and the expected results. You and your doctor can work together to develop a treatment plan that meets your needs.
Cancer treatment is either local therapy or systemic therapy:
- Local therapy: Surgery and radiation therapy are local therapies. They remove or destroy cancer in or near the colon or rectum. When colorectal cancer has spread to other parts of the body, local therapy may be used to control the disease in those specific areas.
- Systemic therapy: Chemotherapy and biologic therapy are systemic therapies. The drugs enter the bloodstream and destroy or control cancer throughout the body.
Surgery is the most common treatment for colorectal cancer.
- Colonoscopy: A small malignant polyp may be removed from your colon or upper rectum with a colonoscope. Some small tumors in the lower rectum can be removed through your anus without a colonoscope.
- Laparoscopy: Early colon cancer may be removed with the aid of a thin, lighted tube (laparoscope). Three or four tiny cuts are made into your abdomen. The surgeon sees inside your abdomen with the laparoscope. The tumor and part of the healthy colon are removed. Nearby lymph nodes also may be removed. The surgeon checks the rest of your intestine and your liver to see if the cancer has spread.
- Open surgery: The surgeon makes a large cut into your abdomen to remove the tumor and part of the healthy colon or rectum. Some nearby lymph nodes are also removed. The surgeon checks the rest of your intestine and your liver to see if the cancer has spread.
When a section of your colon or rectum is removed, the surgeon can usually reconnect the healthy parts. However, sometimes reconnection is not possible. In this case, the surgeon creates a new path for waste to leave your body. The surgeon makes an opening (stoma) in the wall of the abdomen, connects the upper end of the intestine to the stoma, and closes the other end. The operation to create the stoma is called a colostomy. A flat bag fits over the stoma to collect waste, and a special adhesive holds it in place.
For most people, the stoma is temporary. It is needed only until the colon or rectum heals from surgery. After healing takes place, the surgeon reconnects the parts of the intestine and closes the stoma. Some people, especially those with a tumor in the lower rectum, need a permanent stoma.
Chemotherapy uses anticancer drugs to kill cancer cells. The drugs enter the bloodstream and can affect cancer cells all over the body.
Anticancer drugs are usually given through a vein, but some may be given by mouth. You may be treated in an outpatient part of the hospital, at the doctor’s office, or at home. Rarely, a hospital stay may be needed.
Some people with colorectal cancer that has spread receive a monoclonal antibody, a type of biologic therapy. The monoclonal antibodies bind to colorectal cancer cells. They interfere with cancer cell growth and the spread of cancer. People receive monoclonal antibodies through a vein at the doctor’s office, hospital, or clinic. Some people receive chemotherapy at the same time.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area.
Doctors use different types of radiation therapy to treat cancer. Sometimes people receive two types:
- External radiation: The radiation comes from a machine. The most common type of machine used for radiation therapy is called a linear accelerator. Most patients go to the hospital or clinic for their treatment, generally 5 days a week for several weeks.
- Internal radiation (implant radiation or brachytherapy): The radiation comes from radioactive material placed in thin tubes put directly into or near the tumor. The patient stays in the hospital, and the implants generally remain in place for several days. Usually, they are removed before the patient goes home.
- Intraoperative radiation therapy (IORT): In some cases, radiation is given during surgery.
Colon Cancer Treatments
Most patients with colon cancer are treated with surgery. Some people have both surgery and chemotherapy. Some with advanced colon cancer get biological therapy.
A colostomy is seldom needed for people with colon cancer.
Although radiation therapy is rarely used to treat colon cancer, sometimes it is used to relieve pain and other symptoms.
Rectal Cancer Treatments
For all stages of rectal cancer, surgery is the most common treatment. Some patients receive surgery, radiation therapy, and chemotherapy. Some with advanced rectal cancer get biologic therapy.
About 1 out of 8 patients with rectal cancer need a permanent colostomy.
Radiation therapy may be used before and after surgery. Some people have radiation therapy before surgery to shrink the tumor, and some have it after surgery to kill cancer cells that may remain in the area. At some hospitals, patients may have radiation therapy during surgery. People also may have radiation therapy to relieve pain and other problems caused by the cancer.