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Digestive Health Blog

Floss for your gut?


I've launched a new take on colonoscopy and colon cancer prevention called VIP Colonoscopy. As you may have known, changes are afoot in the world of Gastroenterology. If you've seen us for your colonoscopy recently you probably had a discussion before and after about them! Here's a quick refresher and links for more information.

  1. In 2020, surveillance (follow-up) colonoscopy guidelines changed and many patients who previously had less than 3 adenoma-type polyps**, less than 10mm who had been told they needed 5 year interval check-ups not. This is interesting, because at the same time GI doctors were striving hard to improve the detection of every little polyp. The rate that we found polyps in normal risk patients during screening skyrocketed from 20 to 30 to 50 or 60%! Yet, the rate of cancer is only 5% or so. The number of polyps found became a bit of a game, as the magic number of 3 generated more follow-up exams. Interestingly, the criteria for labelling a patient "high-risk" (with "advanced polyp(s)) does not include the number of 3 adenomas as a criterion in other countries. Even these new guidelines admit there is weak evidence that >5 adenomas make a patient high-risk:

2. The age at which we start and stop colonoscopy has changed. By shifting the age to 45, we will better risk-stratify patients at their first colonoscopy. This is the most valuable colonoscopy for cancer prevention, and we strongly recommend it! (Those with family history of "important polyps" or cancer will start earlier) But though we moved up the start date, we have seen multiple studies help define when enough is enough! After age 75, routine colonoscopy is not recommended. What is routine?? A number of studies defined the risk:benefit in patients between the age of 75-85. These criteria are complex, and are important to discuss with a GI doctor before you would schedule a procedure. But we finally have more clarity on this important and individualized care. Last, we better understand the risks even beyond 10 years of follow-up, and though those guidelines have not yet changed there is comfort in seeing data that fewer colonoscopies or hybrid strategies may be reasonable.

3. The advent of molecular tests for colon cancer AND "advanced polyps" has arrived. Many of you have heard of Cologuard, a multi-target DNA test of your stool performed at home. This test has been evolving and improving for 10 years. This year, a second generation version is likely to become available. Data last year showed that detection for "advanced polyps" was nearing 60%. Another test, Geneoscopy, looks for stool-derived eukaryotic RNA and released similar results. Because this test can be performed as often as every 3 years, the compounded probability of finding an important polyp is at or higher than colonoscopy. I'd argue that the definition of these "advanced polyps" matters to this data too, given that we really don't know how many tiny adenomas really increase a person's risk. Instead, a molecular test can be directly associated with risk and signify the important type and risk of a possible lesion inside. The false positive and negative rates are real issues, improving and not barriers to these tests becoming mainstream. An important statistical concept to consider is the "pre-test probability". For example, only 15-20% of patients will be labeled "high risk" at their first colonoscopy. Those in the low/no-risk categories who have a second exam will have a single digit chance of the presence of being labeled as "high-risk". By the third exam, the number is very low. Given what we know, this is a great opportunity for us to consider molecular testing in the later years of life in most patients. As the tests improve in cost and accuracy, their place in our algorithms will grow. This will likely take place over the next few years, meaning it's important to discuss your recommendations with a well-educated physician.

4. OK, so what's "Floss for your gut"?

You know how your dentist gives you floss at your check-ups to remind and encourage you to maintain your health between them? We're now doing that!

I've worked with and studied the microbiome with others for years now. We've seen tests of the microbiome that can identify polyps. We've had theories about why our microbiome is altered, and how we might change it. We've seen links to symptoms and diseases. And now we're finding that "important polyps" may derive from specific changes to your microbes! This may also explain other associations like obesity, sedentary lifestyle, smoking and meat intake.

Working with some of the smartest people I know, we've begun educating patients about microbiome restoration. This is not probiotic based, but instead centered on diet. Specifically, what's missing from our diets based on the most current science available. These recommendations come from myriad stool based studies of the microbiome, but we do not yet advocate for stool microbiome testing, e.g. Viome (though someday I bet we will!)

We provide samples of to our patients not necessarily to encourage purchase but as a link to the studies showing how resistant starches play a large role in this regard. We provide information from Dr. Christopher Damman's fantastic blog and specifically point them to the post on microbiome restoration via the 4Fs.

Last, we collaborate with and who share knowledge and services related to the role of the microbiome in health and disease. We care about your health and colon cancer risks so much that we want to remind and encourage you to maintain your health between your check-ups!

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