What Are My Colon Cancer Screening Options?

Amanda Pressman, MD, FACG

Health care providers agree that the best way to screen for colon cancer is with a colonoscopy. This is the only way to truly look at the colon to identify polyps and remove them before they have a chance to grow into cancer. In this way, a colonoscopy actually prevents colon cancer! No other screening tests can do that, which is why colonoscopy remains the best choice.

Who should be screened?

Colon cancer screening is appropriate for:

  • Adults over 50 with an average risk for colon cancer. However, newer recommendations suggest screening start in the 40s. Talk with your doctor about what is appropriate for you.
  • Those with a personal history of colon cancer, polyps, or other related cancers at any age.
  • Individuals with a family history of colon cancer (one or more first-degree relatives or two or more second-degree relatives) who were diagnosed with colon or rectal cancer before age 60.
  • People who have had a positive result from another screening method in the last six months.
  • Individuals diagnosed with a condition that places them at a higher risk for colon cancer, such as inflammatory bowel disease, ulcerative colitis, Crohn’s disease, or familial polyposis.

Some people, however, are hesitant to have a colonoscopy, fearing the preparation, or perhaps the procedure itself. For some patients, a non-invasive screening option may be offered.

Less invasive options

If you are one of those individuals who would put off screening to avoid a colonoscopy, please talk with your doctor. There are some less invasive, more appealing alternatives available for some people who are not otherwise at high risk.

The following is an overview of each of the less invasive screening tools available.

Cologuard

  • Cologuard is one type of non-invasive screening test. It uses a special kind of technology called stool DNA (sDNA). Upon referral from your doctor, a kit is mailed to you. You then collect a stool sample in the privacy of your own home and mail the kit back to the company for processing.
  • Cologuard can detect cancer and highest-risk pre-cancers (large polyps), but it might not detect small polyps. While both false positives and false negatives do occur, it is considered an accurate screening test.
  • A positive Cologuard result, means that you need to have a colonoscopy. A little more than half of those with a positive result from this test will have something abnormal, such as cancer or a polyp, that is later found during a colonoscopy.
  • If your Cologuard result is negative, it does not necessarily mean you are free of cancer. Of those who had a negative test result, 34 percent of those patients had precancerous polyps found during a colonoscopy.
  • It’s important to keep in mind that Cologuard is not a replacement for a colonoscopy. A colonoscopy is still superior in detecting both cancer and polyps.

Fecal Immunochemical Test (FIT)

  • This screening method for colon cancer tests for hidden blood in the stool, which can be an early sign of cancer. This test does not detect cancer; it only identifies blood from the lower intestine.
  • A normal result means that the test did not find any blood in the stool. However, you may need to perform the test a few times to confirm that blood is not present in your stool.
  • Those with blood in their stool will need further testing; either colonoscopy or sigmoidoscopy, a minimally invasive procedure for examining the large intestine.

CT Colonography

  • A CT colonography is a diagnostic imaging exam that uses low dose radiation scanning to examine the large intestine for cancer or large polyps.
  • It is an effective alternative for patients who have clinical factors that increase the risk of complications from a colonoscopy, such as those who take anti-coagulant medication or have severe respiratory problems. A CT colonography may also be recommended if there is a narrowing of the colon or an obstruction that does not allow visualization of the entire colon during a colonoscopy.
  • This computerized system generates a detailed three-dimensional image of the colon. Like colonoscopy, bowel preparation is required before this procedure.
  • If polyps are found, the patient will need to have a colonoscopy to remove the polyps.
  • This screening method is not recommended for patients who have active Crohn’s, ulcerative colitis, inflammatory bowel disease, or diverticulitis.

It is my hope that every person will be screened for colon cancer at the recommended age or based on past medical or family history. Remember, the best way to screen for and prevent colon cancer is with a colonoscopy.

We are here to help you. Learn more about the Center for Women's Gastrointestinal Medicine at the Women's Medicine Collaborative and the Lifespan Physician Group gastroenterology program.