When were colonoscopies first performed as a routine (i.e. not experimental) medical procedure?
Am I right in assuming that cancer of the large intestine and rectum is more common than cancer of the small intestine? If so, why - especially since the small intestine appears to have a lot more surface area (and therefore more cells to potentially become cancerous)?
Colonoscopy was first done in 1969 and became standard stuff by the end of 70’s. I recall spending some time with a community gastroenterologist (i.e. not university based) in 1980 and we did C-scopes routinely.
Your second question is very interesting. First, cancer of the small intestine is uncommon, much, much less frequent than cancer of the colon and rectum. As to why, here are some guesses:
Transit time through the small intestine is relatively fast so the cells lining it don’t get exposed to “toxins” for protracted lengths of time
By the time things have reached the large intestine (colon), most of the water has been removed making the contents, and any “toxins”, much more concentrated and, thus, more likely to cause ‘damage’.
Bottom line, not only is transit time in the colon slow, sometimes it’s infinite (i.e. there is no movement). So, the cells lining it are subjected to any “toxins” therein for potentially long periods. And, double whammy since they’re more concentrated.
(I would also wonder about the role of bacterial metabolism possibly generating carcinogenic substances. Remember, the small intestine is virtually bacteria-free in normal people. Not so the colon, which is teaming with the critters.)
Wouldn’t this imply that eating fiber, which helps move food more quickly through the colon, would help protect against colon cancer? Is fiber still thought to be beneficial in this regard?
Yes, indeed. Fiber works in part to protect against colon cancer by moving things through faster. But, it also works, maybe more critically, to bind the “toxins” (and “irritants”), thereby making them less able to cause damage (and, of course, flushing them out of the colon along with everything else).
While driving down the highway recently I listened to a radio interview of some doctor who claimed that colonoscopies are, in fact, over rated.
According to this guy, colonoscopies miss most cancers until they are so far advanced that only radical treatment can be applied.
Is this true?
Well, a major purpose of colonoscopy is NOT to detect cancer but, rather, to identify, and then remove any polyps (pre-cancerous growths). By and large, the sequence of colon cancer has been worked out insofar as polyps come first and then transform into cancers. So, if you remove the polyps, you’ve removed the possibility of cancer (until the next ‘batch’ of polyps arise, usually only after several years).
ETA: That is not to trivialize the fact that, yes, early cancers can be detected by C-scopes and their timely removal achieved. That is believed to lead to improved cancer-free survival (which is not as easy to prove as one might think).
OK. Thanks for the clarification.
This recently published study has a different perspective:
“Colonoscopy is associated with a 70% reduced risk for late-stage colorectal cancer (CRC) among people of average risk…according to a study published online March 4 in the Annals of Internal Medicine.”
Colonoscopy is still the gold-standard tool for detecting colon cancer of any stage.
I do look forward to the implementation of highly sensitive and specific blood tests (here’s one promising one in development) which will reduce the need for colonoscopies and removal of polyps which don’t threaten to become malignant (currently we can’t distinguish between low and high-risk adenomatous polyps, which all wind up coming out).
*what did “this guy” consider to be “radical treatment”? Surgery? It would be nifty if we could always catch cancers in the form of early mucosal lesions that are amenable to colonoscopic removal (and I do see those occasionally). Often though, even tiny cancers have begun to invade the bowel wall and a segment of colon needs to come out (however there are less invasive procedures like transanal endoscopic excision for rectal tumors).
Bullshit. Dietary fiber has not been shown to protect against colon cancer.
As usual you selectively cite the literature to back up your claims (which usually have some merit so why you do that is beyond me). And, not only do you cherry pick, you pick old and rotten fruits, thirteen, fourteen years old.
Here is almost the first paper I hit on for a search on dietary fiber and colon cancer. Note the date, 2012. I can give you more but I’m gonna wait until you cough up something from this century.
ETA: I won’t wait. Here’s one from 2011 also showing the benefit.
As long as you continue to make sweeping, outdated, and potentially dangerous medical claims I will continue to refute them.
From the prestigious Cochrane Review:
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003430/abstract
Indeed, the 2008 Cochrane Review which was based in a major part on the three studies you already cited. Now you’re double-dipping.
ETA: And, of course, the studies you cite are regarding “adenomas”, i.e. non-cancerous growths, prevention of which is very different than prevention of cancer.
I recall a lecture given by Denis Burkitt to my med school class. His fame might have been lymphoma, but it was pretty obvious his hobby was bowel movements. I don’t think it would be wildly off the mark to call Burkitt the father of fiber. (More precisely, “fibre” I guess.)
He told us, with absolute sincerity, that we should be taking in so much fiber that “stool breaks would be as common as urination breaks” at meetings. I swear this is close to an exact quote. It was obvious that Dr Burkitt had been deeply moved by the impressive stools he had witnessed in Africa, and it was not hard for him to leap to a conclusion that very high residue/high fiber diets might underpin the concomitant reduction in colon cancer seen in those big-volume-stool populations.
So here’s the thing, from the perspective of my 2c. There are plenty of decent studiesshowing “high-fiber diets” might not do much. I don’t agree with KG that these are old data. I do agree that all those studies don’t paint a complete enough picture, and that there are good alternate studies. But one thing I think all these studies miss is measuring stool volume and making sure that we are not talking about just a “high fiber” diet as if fiber is a medicine you take to prevent cancer.
What we should be measuring is not dietary intake, but instead to what degree each study participant produces frequent, giant, bulky, soft and well-formed stools. Think in terms of a giant tube of well-formed but soft paste easing out and filling the bowl on a regular basis. Not a “high fiber diet” in an individual only dropping a few kids off at the pool every other day.
My gut is that a really good high-fiber diet of the sort envisioned by Burkitt would make a difference. Confounding variables such as other independent carcinogen risks and the nuisance factor trying to get ordinary citizens to do a daily stool measurement it difficult to do a really good study.
On the colonoscopy front, I make the observation that flexible and thin fiber optics along with some fabulous medications have rendered the procedure itself trivial for a patient.
Well; except for the prep.
The study you linked is largely irrelevant to the topic at hand since it looked at fruit and vegetable intake rather than fiber intake per se.
Did it even occur to you that there might be compounds in fruits in vegetables other than fiber that could account for their protective effect against cancer?
Yes, and it evidently occurred to the authors as well who in the abstract, not even buried in the text, said:
“Fibre from cereals and fibre from fruit and vegetables were similarly associated with colon cancer; but for rectal cancer, the inverse association was only evident for fibre from cereals”.
In other words, they looked at cereal fiber versus fruit/vegetable fiber and, in fact, found that cereal-source fiber was more protective than that from fruits and veggies for rectal cancer (and was the same for cancers affecting other parts of the large bowel).
I see what you did there.
Do undertake your own personal study and report back to us* on life with frequent “stool breaks”.
*hopefully with limited detail.
**As for rock groups whose music could be used in public service announcements to promote the new super-high fiber diets, I suggest “Chicago Transit Authority” and “The Move”.
It’s funny how you’ve flip-flopped on this issue. Here’s a post of yours from a previous thread:
http://boards.straightdope.com/sdmb/showpost.php?p=8468898&postcount=11
So does a “balanced diet” with fruit/vegetable/fiber prevent colon cancer or doesn’t it?
Were you misrepresenting the data back then or are you misrepresenting it now?
Thank you for noticing. I was tempted to throw in any number of plays on words, but with the topic at hand they are just too easy.
I am a poster child for large and frequent soft stools, and I highly recommend life with frequent stool breaks over constipation, straining, hernias, laxatives, hemorrhoids, bloating, gas that smells like it’s been stored a week, and so on.
Denis had it right, before it was popular to be a big stool guy. In the end, we should all be anal about getting enough fiber.
PS: Does the argument over high fiber need to go over to GD?
My first intro to colonoscopies was watching a prep for one on a basic cable tv health channel in the 70s. It showed the patient, balls and all, on the table, ready to be scoped. How gross, I thought. Then, less than 10 years later, bloody stools got me my first one in which they clipped two pre-cancerous polyps. (Session described in detail on earlier editions of this board). I’ve had about 4 more scopes since then, with one more polypectomy (benign). I’m due later this year for my 5-year scoping, along with an upper one to check on the Barrett’s Syndrome for the esophagus from GERD. Hopefullly, they won’t do both during the same outage, but that would save a second round trip a during a sedation recovery. When I asked, the doc did say they could do both ends during the same session. He assured me they use different attachments.
I’ve been heavy on the fiber and fruits and often have what my younger office mate called a “sh*t snake” when I told him the helix filled the bowl sump, all in one piece. I know, TMI, TMI.
It’s nice to be stalked* (or let’s say remembered). But riddle me this:
If you hold a position, or you have a belief, and then, over the course of a decade, acquire more information, or become aware of new facts, do you dig your heals in and repudiate what doesn’t agree with you believe, or do you sometimes change your mind?
With you, it’s always confrontational. You start by screaming “bullshit” and you make accusations rather than trying to understand where and why we differ in our interpretation of the same facts. You are a grandstander. You seem not to give a shit about knowledge and care only for being proven right.
Anyway, I’m done here.