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Colorectal Cancer after Childhood Cancer Treatment

Some childhood cancer treatments may increase the risk of developing colorectal cancer.

Risk Factors for Colorectal Cancer in Childhood Cancer Survivors

Radiation to the:

  • Abdomen
  • Spine
  • Pelvis
  • Total body

The risk begins to increase about 10 years after radiation. In the general population, colorectal cancer is most likely to occur between the ages of 45 and 65. Cancer may occur earlier in childhood cancer survivors who had radiation to areas near the colon and rectum.

Some childhood cancer treatments may increase the risk of developing colorectal cancer.

Some childhood cancer treatments may increase the risk of developing colorectal cancer.

Other Risk Factors

  • Previous colorectal cancer or large polyps in the intestine
  • A close relative who had colorectal cancer before age 60
  • Ulcerative colitis or Crohn disease
  • Hereditary colon cancer syndromes, such as familial adenomatous polyposis

Signs and Symptoms of Colorectal Cancer

During the early stages of colorectal cancer, there are rarely signs and symptoms.

  • Most colorectal cancers begin as a polyp.
  • A polyp starts as a small, harmless growth in the wall of the colon or rectum.
  • As the polyp gets larger, it can develop into cancer that grows and spreads.

Signs and symptoms become evident as cancer becomes more advanced. If you have any of these, contact a health care provider immediately.

  • Bleeding from the rectum
  • Blood in the stool or in the toilet after a bowel movement
  • A change in the shape of the stool
  • Cramping pain in the lower stomach
  • A feeling of discomfort or an urge to have a bowel movement when there is no need to have one
  • A change in the normal frequency of bowel movements

Other conditions may cause these signs and symptoms. Your health care provider can evaluate them to find out what may cause them.

What Survivors Can Do

Most people who received radiation to the abdomen, spine, and pelvis will not develop colorectal cancer as a result of treatment. But the risk is higher than people your age who have never had radiation.

It is important to have recommended colorectal screenings to catch cancer early when treatment is most effective.

  1. Ask your oncologist about your risk of late effects.

    Have a yearly physical examination with your health care provider.

    Tell your primary health care provider about your risk. Share a copy of your Survivorship Care Plan, which includes a treatment summary. It includes details about your cancer treatment and information about health problems that may occur because of your treatment.

  2. Childhood cancer survivors who had radiation therapy to the abdomen, spine, pelvis, or total body should get colorectal screening beginning 5 years after radiation or at age 30, whichever is later.

    Talk to your provider about which screening option is best for you. These options include a stool test every 3 years or colonoscopy every 5 years. The colonoscopy is the preferred test, the gold standard in testing for colorectal cancer.

    The colonoscopy is the the gold standard in testing for colorectal cancer.

    The colonoscopy is the the gold standard in testing for colorectal cancer.

  3. Certain lifestyle changes may reduce the risk of colorectal cancer. They will also improve your health.

    Eat a variety of healthy food. Make choices that keep you at a healthy weight.

    Make sure you get plenty of physical activity.


Reviewed: December 2019