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TomBAvoider

Colonoscopy Pro and Con

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I have a PCP whom I generally like, but who adheres pretty strictly to conventional medicine precepts. This can be good and bad. One issue is his insistence on carrying out recommended tests once you reach a certain age. Some tests I just go along with, even though I have no particular interest in them, like PSA, which he routinely orders and which I don't mind insofar as it's part of the same blood sample being taken, so meh, why not (I've had them now for 5 years, and the results are always below 1 ng/mL).

 

Now however, he is pressuring me to have a colonoscopy - no actual issue, just as a routine check. Unlike the PSA test, this is a highly invasive procedure, and I do have some strong concerns. My concerns center around not just the usual discussion of benefit vs risk we've been hashing out on this board, but something I have not seen discussed here at any length (unless I've missed it), is the issue of gut biome.

 

We are learning more and more about the importance of the gut biome, and accordingly, I have attempted to cultivate my gut biome to the degree that I can, and with the limited tools and knowledge available to me. So, I've been careful to consume a ton of fiber of various kinds, fermented foods, prebiotics and probiotics, variety of F&V and grains to increase gut biome diversity . I have also attempted to limit foods which might skew my gut biome toward bad bacteria, avoid antibiotics as much as I can as well as medications which can affect the biome etc. In short, I've tried insofar as I can, to take care of my gut biome.

 

A colonoscopy - the preparation phase in particular - decimate the gut biome. I've tried to google for more info, but as is repeatedly stressed, the issue has not been studied much, though it is acknowledged as a concern. Of the few studies we have, there is strong indication that both the load and the diversity of the biome collapses (31 fold!): https://www.medscape.com/viewarticle/837467 - and the profile of what comes back can be drastically affected, very often in favor of "bad" bacteria (especially for folks with IBD etc.). 

 

There are conflicting reports about the degree to which the biome recovers after this procedure. It seems some strains never come back, other strains are over-represented. Obviously, I would try to replenish with pre-pro-biotics, fiber, F&V etc., but I am worried about the harm this is doing and to what degree this represents a risk of permanent impairment of a gut biome I've spent decades cultivating.

 

Thoughts?

 

 

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Tom,

 

I've had to do quite a few "clean outs" over the last few years for various reasons, including a colonoscopy. I can't say for certain my gut microbiome bounced back unchanged (even Ubiome tests are so variable I wouldn't trust a before/after test to tell me very much). But I can say that it didn't take long (just a couple days) for my gut microbiome to get back to the point where it could process the large amounts of fiber I eat.

 

You seem like the adverturesome type - if you're really concerned you might consider an autologous DIY fecal transplant. :-)

 

Alternatively you could judge for yourself whether a sigmoidoscopy and/or a FIT test might be a reasonably alternative to a full colonoscopy for someone with your CRC risk profile.

 

--Dean

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Thanks, Dean! The DIY FT is a bridge too far even for my adventureous nature :). But I am heartened after hearing about your experience. I consume a metric ton of fiber, and I was very concerned that it would take me a long time to again work myself up to those numbers starting from scratch, so good to hear you can process all the F&V etc. in no time at all. I feel much better now! Thanks again.

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I had a colonoscopy recently one polyp found 20% chance of cancer..... to be repeated in 3 years.. Well worth the effort... One thing..Take any anaesthetic going . I had a sigmoidoscopy a few weeks before v uncomfortable ... Thankfully procedure was free in the UK. 

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[My PCP] is pressuring me to have a colonoscopy - no actual issue, just as a routine check. Unlike the PSA test, this is a highly invasive procedure, and I do have some strong concerns. My concerns center around not just the usual discussion of benefit vs risk we've been hashing out on this board, but something I have not seen discussed here at any length (unless I've missed it), is the issue of gut biome.

A colonoscopy - the preparation phase in particular - decimate the gut biome. I've tried to google for more info, but as is repeatedly stressed, the issue has not been studied much, though it is acknowledged as a concern. Of the few studies we have, there is strong indication that both the load and the diversity of the biome collapses (31 fold!): https://www.medscape.com/viewarticle/837467 - and the profile of what comes back can be drastically affected, very often in favor of "bad" bacteria (especially for folks with IBD etc.). 

 

There are conflicting reports about the degree to which the biome recovers after this procedure.

We've discussed teh subject of colorectal cancer screening in some detail before. I'd first and foremost suggest referring back to that (particularly my first post and subsequent back-and-forth with Dean), since whatever ill effects on the gut microbiome there may be presumably come out in the total mortality wash.

 

Second, one way to avoid any disruption of the microbiome at all is to go with a FIT test rather than a colonoscopy — see discussion in op cit thread.

 

Third, even if you do go with a colonoscopy (either a primary, or as a followup after suspicious FIT), I would expect that a person eating a healthy CR diet is vastly more likely to rebuild a healthy microbiome than an average person, for the same reasons we are more likely to have a better one in the first place: providing all that good food for healthy microbes, and phenolics whose metabolites suppress the unhealthy ones.

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If an individual’s estimated 15-year risk of colorectal cancer is 3% or more, the panel suggests screening with any one of the four options; if the estimated risk is below 3% the panel suggests no screening. These are weak recommendations, which means that in the context of shared decision making, some people with a risk of over 3% are likely to decline screening, and some with a risk under 3% will choose to screen.

 

Age  is a key risk factor.  My age right now alone puts me over 3%,  even at a low BMI and zero additional risk factors.

I've had two colonoscopies.  I'm extremely glad I did,  no regrets at all. The last one went so well,  so smoothly,  so easily--the whole process from beginning to end was in fact enjoyable.    Prep consisted of a three day diluted vegetable juice fast (which I continued after the colonoscopy for a total of five days),  a  few enemas and a small prep check to confirm I was fully cleaned out.   During with colonoscopy I was slightly sedated via fentanyl,  which was quite pleasurable.  I watched the video throughout and chatted with the doc.  He commented that I had done an excellent prep and that I had a normal healthy-looking colon.  Clean bill of health.  Peace of mind.  No gut problems whatsoever. 

Edited by Sibiriak

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The big unknown of course is what are the long term consequences of having this intervention done. A hose up your ass, laxatives drugs to sedate etc.  We do know that punctures occur and can be deadly. We might find in the long run that similar to prostrate screening more harm is being done than good. People tend to focus on colonoscopy = lower risk of getting colon cancer. True but who knows what the real risks are in the long run. I believe in the, first do no harm approach, when possible,. Another point is that the non intervention fecal blood test looks almost as effective at preventing colon cancer mortality as a colonoscopy. That’s why after having two colonoscopies I now simply do the blood test annually. See graphics comparing the the various screenings in the article

Edited by mikeccolella

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Mike,  it's a personal decision.  In my case,  I had  confidence that the doctor performing the colonoscopy was highly competent,  and I had the knowledge and experience to do an excellent (and enjoyable) prep. In those  circumstances,  the chance of a puncture are extraordinarily  small.   And it's not true that long-term consequences are simply a  "big unknown" as you suggest.     Furthermore,   I do not believe a fecal test can prevent colon cancer incidence as a colonoscopy can when problematic polyps are detected and removed.  Besides, "almost as effective"  is not at all reassuring to me when it comes to a life and death issue  (not to mention having to deal with all the pain, stress, inconvenience, discomfort and indignity of doing what it takes to survive colon cancer.)

Again, it's a personal choice, as the article you posted discusses, risks vs benefits assessment being different in each individual case .    I wouldn't  second guess anyone else's informed decision.

 

 

 

 

Edited by Sibiriak

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My experience with my two colonoscopies is very similar to Siberiac's.  Assuming that you have the services of a competent gastroenterologist, it's a good idea.

 In my case, both colonoscopies showed a perfectly healthy colon -- nothing that suggested the possibility of something precancerous.  I'm 80, and will get another one in about 5 years -- despite the idiotic accepted idea that there's "no need" after age 70.

  --  Saul

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https://www.healthline.com/health-news/dreading-colonoscopy-other-effective-tests-for-colon-cancer-032015#1

 

see the above or the other reference wrt to my rationale here. Bottom line fobt every year is as effective as a colonoscopy every ten years. If your 15 year risk is like mine 4.3% then the probality that you will get colon cancer is remote and doing a fobt each year protects you just as well as the invasive and possibly dangerous procedure that you expose yourself too when an fobt yearly will likely never send you to the gastro doc to have a sharp tool shoved up your ass, medicines that are dubious etc. if the unlikely positive result is that there is blood in your stool then one takes the risk and goes to the gastro doc and gets his colonoscopy. 

But certainly each individual makes their choices as they see fit

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If a test can definitely detect pre-cancerous polyps, then the advantage of a colonoscopy drops significantly. Accordingly to the article Mike linked to, sDNA is supposedly such a test, but I don't know how accurate it is - does it definitely flag a polyp 100% of the time? I don't know. Keep in mind that a colonoscopy does not guarantee 100% polyp detection either - not only does it depend on the physician administering the test, but there are regions of the colon that the colonoscopy does not properly reach. 

*If* a test would definitely discover polyps, then the only advantage a colonoscopy would have would be the ability to immediatly excise that polyp. Removing polyps seems a good idea, because according to studies this kind of prevention is key to reducing CC, as merely catching CC early seems to confer no survival advantage :( - either way, whether discovered by a test like sDNA or colonoscopy, you still should remove any pre-cancerous polyps ASAP.

It might be that if you've already have had at least one colonoscopy, and it detected no polyps, then it's probably quite fine to just rely on tests such as the fobt or sDNA - assuming you are not at high risk due to lifestyle factors or family history. 

In any case I've had my colonoscopy, so I'm good for awhile. It is my understanding that it takes an average of about 10 years for a polyp to develop into cancer, so if you've had a colonoscopy that showed you have zero polyps, even if you got a polyp the next day, presumably it would get caught on your next scheduled colonoscopy (every 10 years) before it turned fully cancerous.

Anyhow, if there's a reliable test that definitely detects pre-cancerous polyps, I'm quite happy not to have another colonoscopy what with its attendant risks and disruption to the gut biome. YMMV. 

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