Colon Cancer Screening: FIT Card

Having a realization that colon cancer is a serious disease that is preventable is half the battle. Once you make the commitment to be tested for colon cancer, there is another challenge to determine which test is best for you. Some tests need to be performed every year, while others can be completed every 5 to 10 years. Some tests can detect early-stage disease, while others can find pre-cancers. There are 3 tests we will discuss. One test can detect blood and another cancer DNA in the stool. We will also discuss colonoscopy, which is considered the gold-standard for finding colon cancer. For this discussion, let’s find out more FIT stool blood card.

One of the most common tests for colon cancer is called a FIT, which stands for Fecal Immunochemical Test. The FIT measures blood in the stool, with the understanding that colon cancer tends to bleed. This test does not detect cancer, only blood. It is our hope that a positive FIT will lead us to another test that will find cancer. This other test is a colonoscopy, which is the gold standard to detecting colon cancer. Therefore, if FIT is positive, a colonoscopy must be performed as soon as possible. Once a FIT is positive, you cannot repeat the FIT again to see if it turns negative a second time. Once a FIT is positive, it cannot be ignored nor repeated with different expectations.

The are many advantages to the FIT. One of the advantages involves its convenience. This test involves passing a bowl movement in the toilet and using a long brush, similar to a paint brush, to smear a sample of you stool on a card. Instead of a long brush, your kit may have a small scoop or a long stick. You would then place this card in the mail and receive results days later. Also, there is no preparation needed for this test, such as cleaning your bowel, nor medications that need to be held. The FIT can be performed at home without the need for sedation, which are medications a doctor may use to make you briefly unconscious to complete a test. As a result, there is no recovery time and no one needs to “drive you home” after your test.  It is important to remember that a negative FIT does not mean you do not have cancer, it only signifies you do not have blood in your stool. The FIT card needs to be completed every year to make this an effective screening test for colon cancer.

A major disadvantage of the FIT is its inability to lead us to all colon cancers and adenomas. How precise is the FIT card?  The FIT card is about 74% sensitive for picking up colon cancer. However, the FIT does a poor job of detecting adenomas. Remember, an adenoma is the “middleman” of colon cancer. Each adenoma has about a 5% chance of turning into cancer within 7 to 10 years. The FIT card only picks up about 23% of adenomas that are later found on colonoscopy. If the adenomas are small, then the FIT card will only find adenomas in about 7% of the cases. (1,2)

Here is the bottom line: The FIT card is convenient, but it is not a perfect test. The FIT card does not find cancer directly; instead, it detects blood. Yet, what if a colon mass is not bleeding at the time, you perform the test? What if you have a pre-cancerous mass that does not bleed? Since there are some imperfections in this test, a FIT card should be completed each year, but a negative result does not mean you do not have cancer. It means you do not have blood in your stool. Also, the FIT card is not good at leading us to the “middleman” of cancer, adenomas. If you are truly concerned about colon cancer, consider undergoing a colonoscopy, which is the gold standard for finding colon cancer and adenomas. With that being said, since the FIT is convenient, we find that many individuals are compliant with it. If you are unable to get a colonoscopy because of issues with sedation or the inability to hold important medications, such as aspirin or blood thinners, then the FIT may be right for you.

REFERENCES
1. Zauber A, Knudsen A, Rutter CM, et al. Evaluating the Benefits and Harms of Colorectal Cancer Screening Strategies: A Collaborative Modeling Approach. AHRQ Publication No. 14-05203-EF-2. Rockville, MD: Agency for Healthcare Research and Quality; October 2015r.
2. Knudsen AB, Zauber AG, Rutter CM, et al. Estimation of Benefits, Burden, and Harms of Colorectal Cancer Screening Strategies: Modeling Study for the US Preventive Services Task Force. JAMA 2016; 315:2595.