Cancer of the Colon or Rectum after Childhood Cancer


Risk for cancer of the colon or rectum (colorectal cancer) in adulthood is higher for some survivors of childhood cancer than it is for people of the same age in the general population. Here’s what you need to know to assess your risk and help prevent colorectal cancer.

Am I at Risk?

Research has shown that people who were treated with moderate to high doses of radiation to the stomach, pelvis, or spine in childhood, adolescence, or young adulthood have a higher risk for colorectal cancer than people of the same age who never had radiation.

Other factors that increase risk include:

  • a history of colorectal cancer or large intestinal polyps,
  • close relatives who had colorectal cancer before age 60,
  • ulcerative colitis or Crohn’s disease, and
  • hereditary colon cancer syndrome (such as familial adenomatous polyposis).

Risk for colorectal cancer begins to increase around 10 years after radiation.&

Does Colorectal Cancer Have Symptoms?

People with colorectal cancer rarely have symptoms at first. This is why screening is so important. Symptoms may begin once the cancer is more advanced. See your doctor right away if you have any of these symptoms:

  • bleeding from your rectum,
  • blood in your stool or in the toilet after a bowel movement,
  • change in the shape of your stool,
  • cramping pain in your lower stomach,
  • discomfort or urge to have a bowel movement when there is no need to have one, or
  • change in how often you have bowel movements.

Your doctor will help figure out the root of these symptoms.

What If I Am at Risk for Colorectal Cancer?

Although most people who received radiation won’t develop colorectal cancer, it’s still important to monitor your colon. If colorectal cancer is found early enough it can usually be cured. There are also healthy choices you can make to lower your risk.

Discuss Screening with Your Doctor 

Check your treatment records to find out how much radiation you received for childhood cancer (see related Health Link: “Long-Term Follow-Up after Childhood Cancer”).

If you received radiation to the stomach, pelvis, or spine at doses of 30 Gy (3000 cGy/rads) or higher, you should have a colonoscopy at least every 5 years starting at age 35 or 10 years after radiation (whichever occurs last). When calculating your radiation exposure, make sure to include any radiation from total body irradiation. 

If you received less than 30 Gy (3000 cGy/rads), or if you had total body irradiation, you might still be at risk, but no studies have confirmed this. Talk with your doctor about when you should begin having colonoscopies.

Eat a Healthy Diet 

To lower your risk for colorectal cancer, eat a variety of healthful foods with a focus on grains, fruits, and vegetables.

  • Eat five or more servings of a many kinds of vegetables and fruits each day.
  • Choose whole grains over processed or refined grains and sugars.
  • Limit red meat, especially processed meat (like hot dogs and bologna) and those high in fat.
  • Choose foods that help you keep a healthy weight.

Be Physically Active 

To lower colorectal cancer risk, try to get at least 30 minutes of moderate physical activity, such as brisk walking, on five or more days of the week. Getting 45 or more minutes of moderate to vigorous activity (such as running) on at least five days of the week may further lower your risk for colon cancer.

Childhood Cancer

Medical Information

Research

Coping with Cancer

Get Involved

About Us