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Treatments for Colorectal Cancer

The primary treatment for cancers of the colon and rectum is surgery. For cancers that have not spread, surgery alone may cure your cancer.

  • Depending on the location and stage of your cancer, your doctor may recommend chemotherapy and/or radiation therapy either before or after surgery.
  • For rectal cancer, radiation is usually given with chemotherapy. It can be given before surgery (called preoperative or neoadjuvant therapy) or after surgery (called postoperative or adjuvant therapy). Depending on the location and stage of your tumor, preoperative therapy may allow the surgeon to spare your anal sphincter. This would avoid the need for a permanent colostomy and may reduce the chance of the cancer coming back.

Understanding Radiation Therapy

Radiation therapy, sometimes called radiotherapy, is the careful use of radiation to safely and effectively treat cancer.

  • Cancer doctors called radiation oncologists use radiation therapy to try to cure cancer, to control cancer growth or to relieve symptoms, such as pain.
  • Radiation therapy works within cancer cells by damaging their ability to multiply. When these cells die, the body naturally eliminates them.
  • Healthy cells are also affected by radiation, but they are able to repair themselves in a way cancer cells cannot.

After a diagnosis of colorectal cancer has been established, it's important to talk about your treatment options with a radiation oncologist.

External Beam Radiation Therapy

External beam radiation therapy involves a series of daily outpatient treatments to accurately deliver radiation to the area at risk.

  • Before beginning treatment, you will be scheduled for a simulation to map out the area being treated. This will involve having X-rays and/or a CT scan. You will also receive tiny tattoo marks on your skin to help the therapists precisely position you for daily treatment.
  • Treatment is given once a day, Monday through Friday, for about six weeks.
  • Newer technologies like intensity modulated radiation therapy (IMRT) are being evaluated for use in treating colorectal cancer. Ask your radiation oncologist for more information on these treatments.

Possible Side Effects

People with colorectal cancer often get chemotherapy while they are receiving radiation. Side effects during treatment result from both the local effects of radiation to the pelvic area and the systemic effects of chemotherapy throughout the body.

  • Possible side effects from radiation include more frequent bowel movements, diarrhea, abdominal cramping, pressure or discomfort in the rectal area, urinating more often, burning with urination, skin irritation, nausea and fatigue. These are usually temporary and resolve after your treatment ends.
  • Chemotherapy side effects will depend on the specific drug you receive.
  • Side effects are not the same for all patients. Ask your doctor what you can expect from your specific treatment.
  • Many of these side effects can be well controlled with medications and changes to your diet. Tell your doctor or nurse if you experience any discomfort so it can be treated.