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Colorectal Cancer Screening Exams

Men and women at average risk for colorectal cancer should get a screening colonoscopy every 10 years beginning at age 45.

Regular screening exams for colon cancer and rectal cancer can find cancer at an early stage. When found early, the chances for successfully treating the disease are greatest.

Along with regular exams, practice awareness. This means you should be familiar with your body. That way you’ll notice changes, like bleeding or unusual bowel movements. Then, report them to your doctor without delay.

Your doctor can help you decide if you should continue screening after age 75. MD Anderson doesn’t recommend screening for adults after age 85.

What is a colonoscopy?

During a colonoscopy, you will be sedated. Your doctor will insert a flexible tube with a video chip into your rectum and through the length of your large intestine (colon). Your doctor will examine the surface of your colon as they withdraw the tube.

Your colon must be completely clean in order for your doctor to see any abnormalities. The day before the test, you will prepare by avoiding solid foods and drinking only clear liquids. You also have to drink a solution that will cause you to go to the bathroom - probably several times – so there is absolutely no waste in your colon.

One of the benefits of colonoscopy is that your doctor can remove precancerous polyps during the exam without scheduling another procedure.

Alternative tests to colonoscopy

Virtual colonoscopy - If you choose virtual colonoscopy over regular colonoscopy, MD Anderson recommends you get the test every five years starting at age 45. A colonoscopy will be performed if polyps are found.

During a virtual colonoscopy, your doctor performs a low-dose CT scan of your abdomen and pelvis to create 3D images. These images show polyps and other abnormalities inside your colon and rectum.

A virtual colonoscopy requires the same preparation as a colonoscopy. Your colon must be completely free of waste in order for your doctor to get a clear image. Virtual colonoscopies can miss small or hard-to-see polyps.

If your doctor does find polyps or anything suspicious, you will need to get a regular colonoscopy. This test will not be considered a screening test, but a diagnostic test to diagnose the problem. Your insurance may bill this second colonoscopy differently.

If you choose a virtual colonoscopy, check with your insurance provider before scheduling an exam. Not all insurance providers cover the cost of this exam.

Stool-based tests - If you choose stool-based tests, MD Anderson recommends you get tested beginning at age 45. Your doctor will recommend a colonoscopy if signs of cancer are found. Stool-based tests can be performed annually or every three years, depending on the test. There is no preparation for this type of test.

Stool-based tests look for signs or "markers" for cancer in your stool. Here are the two types of stool-based tests that MD Anderson recommends:

Stool DNA tests can detect changes in DNA that happen as colon cancer develops. These combine testing for changes in stool DNA with a fecal immunochemical test (FIT). These are the most accurate of the stool-based tests. This test should be done every three years.
Fecal immunochemical tests (FIT) look for proteins found in blood. This can let your doctor know that there may be blood in your stool, which can be a sign of colon cancer. This test should be done every year.

Colorectal cancer symptoms and risk factors

Adults at increased or high risk are more likely to get colorectal cancer. This doesn’t mean you’ll definitely get cancer. But, you may need to start screening at an earlier age, get additional tests or be tested more often. Learn more about colorectal cancer risk factors.

Colorectal cancer often does not have symptoms in the early stages. Most colon cancers begin as polyps, small non-cancerous growths on the colon wall that can grow larger and become cancerous. As polyps or cancers grow, they can bleed or block the intestines. If you have symptoms of the colorectal cancer, talk to your doctor. You may need to start screening at an earlier age, get additional tests or be tested more often.

Colorectal cancer recurrence

If you’ve had colorectal cancer, you need a different plan to check for recurrence. This includes periodic colonoscopy. Print the survivorship screening chart below that best describes your cancer type and share it with your doctor. Your doctor can use this chart to create a more tailored plan for you.

Reduce your colorectal cancer risk

Nothing you do can guarantee that you won't get colorectal cancer. But making the following healthy lifestyle choices will reduce the chances that you will get the disease.

Get screened. Screening exams for colorectal cancer can find the disease early, when it’s most treatable.
Maintain a healthy weight. Excess body fat is linked to an increased risk of colorectal cancer.
Exercise regularly. Aim for at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise each week.
Eat a plant-based diet. Make 2/3 of your plate vegetables, whole grains and fruit. The other 1/3 should be lean animal protein or plant-based protein.
Limit red meat. The more you eat, the more you increase your risk. Aim to eat no more than 18 ounces of cooked red meat each week. Red meat includes beef, pork and lamb.
Avoid processed meat. This includes bacon, deli meats and hot dogs.
Limit alcohol. For cancer prevention, it’s best not to drink alcohol.
If you smoke, stop. If you don’t smoke, don’t start

The screening plans on this page apply to adults expected to live for at least 10 years. They’re not for adults who have a health condition that may make it hard to diagnose or treat colorectal cancer.