Stool DNA Testing for Colon Cancer

[ASTEPHENS33]

Has anyone used this/had experience with it, that they can share? Its called Colonguard - http://www.cancer.org/cancer/news/featu ... lon-cancer. A friend has it recommended to her. thanks

[Lydia666]

Thanks for the info!

[Jacques]

Has anyone used this/had experience with it, that they can share? Its called Colonguard - http://www.cancer.org/cancer/news/featu ... lon-cancer. A friend has it recommended to her. thanks

I have not had any experience with this test. However, I noticed that the U.S. Preventive Services Task Force has decided not to recommend it for general colon cancer screening. To understand why, you need to read and understand the fine print of the Task Force's most recent recommendation

Task Force Recommendation for Colorectal Cancer Screening (2015) (see FIT-DNA paragraph)
http://www.uspreventiveservicestaskforce.org/Page/Document/draft-recommendation-statement38/colorectal-cancer-screening2

As I understand it, the situation is this: The FDA has approved this test, basically because it has the highest sensitivity of any stool test available. What this means is that if you indeed have colon cancer, it is almost sure to find it. However, this test also has a low specificity. What this means is that this test generates more False Positives than other available stool tests, i.e., your test result may say "Positive for colon cancer" but it might very well be wrong.

The task force apparently thinks that too many patients will be sent off to have a colonoscopy when this is not in fact necessary and it would put too many patients at additional risk of an unnecessary invasive procedure. Also, the FIT-DNA test is more expensive than the standard Fecal Immunochemical Test (FIT) stool test.

Alternative Tests
...Screening with computed tomography (CT) colonography and multitargeted stool DNA (FIT-DNA) testing may be useful in select clinical circumstances. However, there is less mature evidence to support these methods, resulting in greater uncertainty about their net benefits and the most appropriate situations in which to use them.
. . .
Ref: Imperiale TF, Ransohoff DF, Itzkowitz SH, Levin TR, Lavin P, Lidgard GP, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med. 2014;370(14):1287-97.

Another question to ask is this: Why is your friend considering a DNA stool test? Is it because she belongs to a known high risk group for colon cancer and wants to be tested even though she does not have any symptoms, or is it because she has troublesome bowel symptoms that need to be diagnosed and treated? There is a difference between these two objectives. The DNA stool test will test only for colorectal cancer. It cannot be used to diagnose benign conditions such as ulcerative colitis, IBS, hemorrhoids, diverticulitis, etc.

[me2]

The task force apparently thinks that too many patients will be sent off to have a colonoscopy when this is not in fact necessary and it would put too many patients at additional risk of an unnecessary invasive procedure. Also, the FIT-DNA test is more expensive than the standard Fecal Immunochemical Test (FIT) stool test.

That's fine when you're trying to reduce spending as a government or insurer. It's fine when you're trying to limit the need for more GI doctors doing endoscopies.

It's not fine as a patient, where you want your polyps removed before they become cancerous and detectable by fecal tests.

If your circumstances warrant screening, they call for a colonoscopy. You can do a Miralax prep which is flavorless, and get enough drugs you won't remember the procedure.