This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science at CTCA.
This page was updated on June 9, 2022.
Treatment for colorectal cancer may involve various steps. In addition to surgery and powerful drugs such as chemotherapy, radiation therapy may be a recommended part of your personalized care plan. In general, radiation therapy uses high-energy X-rays to kill cancer cells. In the treatment of colorectal cancer, it’s more widely used in cases of rectal cancer than colon cancer. Sometimes, chemotherapy is given at the same time as radiation therapy (a process called chemoradiation) in order to make the radiation therapy work better.
Although used less often for colon cancer than rectal cancer, radiation therapy for colorectal cancer may be an option:
Radiation therapy is delivered in a few different ways, depending on the specific source of the radiation:
The length of radiation treatments varies depending on the radiation technique. For instance, with EBRT, you may receive radiation therapy for a few days or weeks. The most common schedule for endocavitary radiation therapy is four treatments lasting just minutes each and given at two-week intervals. Interstitial brachytherapy may be administered just once or a couple of times a week over a few weeks.
The type of cancer also determines the length of time you’ll have radiation therapy. For example, when it’s given prior to surgery for rectal cancer, it may be started five or six weeks in advance of the surgery date.
Talk to your care team to get a better understanding of how long your radiation therapy may last.
As with other cancer treatments, radiation therapy may cause side effects. Most go away when treatment stops, but some may continue. Possible side effects include:
Sexual challenges may include infertility when radiation therapy is delivered to the pelvic regopm. Talk with your care team in advance to learn more about how radiation therapy could affect your sexual health and what options you may have for preserving your fertility.