Radiation therapy uses X-rays to destroy colorectal cancer cells and shrink tumors. It is often used to treat rectal cancer, usually combined with surgery. It is used less often to treat colon cancer. It may also be combined with chemotherapy.

Other Treatment Choices

Radiation may be given:

• Externally, using a machine outside the body that points a beam of radiation at the tumor.
• Internally, by placing tiny radioactive "seeds" next to or into the cancer.

Compared to surgery alone, radiation given before surgery may reduce the risk that rectal cancer will return and may help you live longer.⁹

What To Think About

Clinical trials are designed to find better ways to treat people with cancer and are based on the most current information. Some people who meet the criteria for participation choose to enroll in such clinical trials.