RADIATION THERAPY FOR COLORECTAL CANCER
Facts to Help People Understand Treatment

External Beam Radiation Therapy

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

• Before starting treatment, a simulation to map the area being treated is scheduled. This involves having X-rays and/or a CT scan. Tiny tattoo marks are placed on the 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 3-dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiation therapy (IMRT) are being considered for use in treating colorectal cancer. Ask your radiation oncologist for specific information on these treatments.

Possible Side Effects

People with colorectal cancer often receive both chemotherapy and radiation. Side effects can occur as a result of 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 fatigue, more frequent bowel movements, diarrhea, abdominal cramping, pressure or discomfort in the rectal area, urinating more often, burning with urination, skin irritation, and nausea. Symptoms are usually temporary and resolve after treatment ends.
• Chemotherapy side effects depend on the specific drug used.
• Side effects vary among patients. Ask your physician what to expect from your specific treatment.
• Many side effects can be relieved with medications and dietary changes. Talk to your doctor or nurse about any discomfort so it can be treated.

Learning About Clinical Trials

Current standard radiation therapy treatments are a result of studies called clinical trials completed many years ago. The radiation oncology team is constantly exploring new ways to treat people with colorectal cancer tumors through ongoing clinical trials. For more information, please contact the following organizations:

National Cancer Institute
www.cancer.gov/clinicaltrials

Radiation Therapy Oncology Group
www.rtog.org

Helpful Web Sites On Colorectal Cancer

American Cancer Society
www.cancer.org

Colon Cancer Alliance
www.ccalliance.org

Colorectal Cancer Network
www.colorectal-cancer.net

Cancer Research and Prevention Foundation
www.preventcancer.org

National Colorectal Cancer Research Alliance
www.nccra.org

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