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 type of test called FIT can also be helpful. Moreover, the FDA has just approved a blood test that should make it a little easier to get screened for colon cancer as well.
New Approaches to Colon Cancer Screening:
The gold standard for detecting colorectal cancer is a colonoscopy repeated at periodic intervals. In addition to detecting cancer, this procedure allows the physician to remove any polyps (precancerous growths) that are found. However, many people are reluctant to schedule colonoscopies. They may feel too daunted to prepare for the procedure. As a result, as many as one-fourth or even half of those who could benefit from screening don’t get it.
The new test, approved for adults 45 or older, is based on DNA in blood. Both polyps and tumors shed some of their DNA, and this analysis detects it when the tumors are still small. In evaluating this test, called Shield, investigators found that it detected 87 percent of cancers at an early stage, which are usually highly treatable. By contrast, colonoscopies find about 95 percent of these tumors.
If the Shield blood test detects tumor DNA, the patient will need a follow-up colonoscopy. Medicare is expected to cover the cost. People paying out of pocket might have to pay as much as $900.
Prepping for a Colonoscopy:
As noted, 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 a few years ago that the over-the-counter FIT (fecal immunochemical test) protocol can be surprisingly helpful (Imperiale et al, Annals of Internal Medicine, Feb. 26, 2019).
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 proteins in the stool. It is surprisingly accurate, though not quite as definitive as a colonoscopy. A recent review published in the Annals of Internal Medicine (April 2024) 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.
Ask Your Doctor About Colon Cancer Screening:
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. Alternatively, inquire about the Shield blood test. Using one of these tests to detect colon cancer early could save your life. One reader is pleased to be in that category.
Using FIT to Find Colon Cancer:
Q. FIT found my colon cancer! I had colonoscopy, then surgery, and then chemo pills that I am still on. Thank God I did the FIT test.
A. FIT stands for fecal immunochemical test. This at-home affordable stool test is quite accurate (Annals of Internal Medicine, April 2024). A positive result does call for a colonoscopy. Ideally, that is then followed by the appropriate treatment.
