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FIT | Can You Detect Colon Cancer Without a Colonoscopy?

FIT | Can You Detect Colon Cancer Without a Colonoscopy?
Roll of toilet paper on a toilet concept for constipation and bowel movement

Have you ever had a colonoscopy? It might not be the most pleasant screening test ever devised, but it does save lives. Colon cancer is a leading cause of cancer death, and a colonoscopy is a way to detect colon cancer relatively early. A new type of test called FIT can also be helpful.

Gastroenterologists recommend regular colonoscopies to detect colon polyps that could turn into cancer. We highly endorse such testing, but we recognize that many people don’t like the prep. In addition, people without insurance may find the cost daunting. That’s why we were excited to learn that the over-the-counter FIT (fecal immunochemical test) protocol can be surprisingly helpful (Imperiale et al, Annals of Internal Medicine, Feb. 26, 2019).

Prepping for a Colonoscopy:

If you have ever had a colonoscopy, you know the routine. You have to cut back on healthy high-fiber foods a couple of days before the procedure. You eat no seeds, nuts, whole grains or dried fruit. The day before the colonoscopy all you get is clear liquids.

Either the night before the procedure or the morning of exam, you will likely drink about what seems like an impossible amount of a nasty-tasting prep liquid that will clean you out. (Do not stray far from the bathroom!) The rigor of preparing for a colonoscopy is a small price to pay if you are able to detect colon cancer while it is still easy to treat, however.

What About FIT (Fecal Immunochemical Test)?

The over-the-counter FIT procedure detects hidden blood in the stool. It is surprisingly accurate, though not quite as definitive as a colonoscopy. A recent review of 31 studies published in the Annals of Internal Medicine (Feb. 26, 2019) shows that a home stool test to screen for colorectal cancer may be a useful option. In these studies, 120,000 people completed stool tests before their colonoscopies.

The study demonstrated that such fecal immunochemical tests pick up 75 to 80 percent of cancers. Adjusted for higher sensitivity, they may detect as many as 91 percent of cancers, but they then have a higher rate of false positives. Colonoscopies are believed to detect 95 percent of colorectal tumors.

Although it is not perfect, the FIT protocol can help people at average risk. FIT is not appropriate for people with an especially high chance of colon cancer. Anyone who has a positive result on a FIT stool test will need a colonoscopy as a follow-up.

How Does FIT Work?

Colon cancer is not the only cause of blood in the stool. A number of conditions can affect the results of FIT. They include hemorrhoids, anal fissures, hard stools, Crohn’s disease, colitis and proctitis related to radiation treatment for prostate cancer. People who take a lot of NSAID-type pain relievers like aspirin, ibuprofen or naproxen may also get a false positive test result (Stegeman et al, International Journal of Cancer, Nov. 15, 2013). 

The FIT kit is available online without a prescription. If your doctor recommends a fecal immunochemical test, your insurance company may pay for it, though.

There are a couple of procedures. One involves putting a collection paper sling under the toilet seat. It comes with the kit. Your bowel movement is caught in the paper sling. The kit also contains a tube with a screw cap containing a brush or applicator. You take a sample of stool and put the applicator back into the tube and tighten it. You then send the tube to the company in the special pouch that is supplied. They contact you with the results.

Another kind of FIT kit gives you results at home. You unscrew the “wand” that is supplied with the tube. It is used to collect a small amount of stool from toilet paper. This applicator gets screwed back into the tube and is shaken. Three drops of liquid are placed on a plastic “cassette” and the results are read as positive or negative within a few minutes.

If your doctor has been trying to get you to schedule a colonoscopy and you haven’t done so yet, ask whether a FIT test would be appropriate for you. Using such a test to detect  colon cancer early could save your life. 

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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