Colorectal Cancer

Screening tests can prevent colorectal cancer. Screening tests look for a certain disease or condition before any symptoms appear. Regular screening is recommended beginning at age 50 for people with an average risk for colorectal cancer. For people with an increased risk for colorectal cancer, earlier screening is recommended.

Fewer than half of people who are older than 50 are screened for colorectal cancer. According to the American Cancer Society, if everyone were tested, tens of thousands of lives could be saved each year.

The following guidelines are for people who do not have an increased risk for colorectal cancer.

Experts have not yet set guidelines for how often a person should have the stool DNA test (sDNA) or computed tomographic colonography (CTC).⁸

You will need to begin routine screening earlier than age 50 and have it more often if you have a higher risk for colorectal cancer.

Virtual colonoscopy (also called computed tomographic colonography or CT colonography) uses X-rays and a computer to take pictures of the inside of your large intestine. It may be used as a screening test for people who do not have an increased risk for colon cancer or for people who cannot have a colonoscopy. For people who have increased risk, regular colonoscopy may be better because it allows your doctor to remove polyps (polypectomy) and take tissue samples during the screening procedure. Virtual colonoscopy is not widely available, and the cost may not be covered by insurance.

Which test should I have to screen for colorectal cancer?

Here are other things you can do to help prevent colorectal cancer:

• Watch your weight. In trials, people who were overweight got colorectal cancer more often than those who were not. And people whose extra fat was in the waist area got it more often than people whose extra fat was in the hips or thighs. For more information, see the topic Healthy Weight.
• Eat well. Eat a variety of healthy foods, especially fruits and vegetables. Eating more vegetables, fruits, legumes, fish, poultry, and whole grains helps prevent cancer. Limit your consumption of animal fat. Take a calcium supplement daily. For more information, see the topic Healthy Eating.
• Limit drinking. People who drink more than 2 alcoholic drinks a day—and especially those who drink more than 3 drinks a day—have a slightly higher risk for colorectal cancer.⁵
• Get active. Keep up a physically active lifestyle. Being fit also leads to an improved sense of well-being, improved appearance, and increased stamina and strength. For more information, see the topic Fitness.
• Do not smoke. Smokers have a higher rate of cancer than nonsmokers.² For more information, see the topic Quitting Tobacco Use.

Researchers continue to investigate ways to use drugs to prevent cancer. Drugs being studied include hormones used to treat symptoms of menopause, a mineral called selenium, and vitamin E.

What to think about

If you have a strong family history of colon cancer, you may want to talk to your doctor or a genetic counselor about having a blood test to look for changed genes. Genetic testing can tell you whether you carry a changed, or mutated, gene that can cause colon cancer. Having certain genes greatly increases your risk of colon cancer.

You have a strong family history if each of the following is true:

• You have at least three relatives who have had colon cancer, and at least one of them is a parent, brother, or sister.
• Those relatives are spread over two generations in a row (for example, a parent and a grandparent).
• One of those relatives got cancer before age 50.