The short answer, unless I'm mistaken, is that the trial didn't measure the effectiveness of colonoscopies. It measured the effectiveness of being invited to have a colonoscopy. That plus "ten years of follow-up is a relatively short period of time for colorectal-cancer development", per a source in the article.
How would you design such a trial? You cannot force people to undergo a colonoscopy.
But if you just compare the people who SELF SELECTED themselves to undergo the trial then you introduce the biases that you attempted to overcome by using a randomized controlled trial.
The problem with this news feature is that it assumes a-priori that screening for colorectal cancer is effective, without good evidence.
Screenings result in false positives and in complications. One has to show rigorously that screening has net benefits.
I thought we have learned our lesson from the PSA fiasco.
Their main criticism of the study is this:
> If the compliance rate had been 100%, the researchers’ analysis showed, the test would have reduced cancer risk by 31% — from 1.22% to 0.84% — and it would have reduced the risk of death from colorectal cancer by 50% — from 0.3% to 0.15%.
But the study did no such thing. There's no way for the study to do such a thing.
What they describe is the comparing the results on the SELF SELECTED group of those who decided to go and get screened. This is no longer a randomized controlled trial.
We have no idea why those who decided to get screened did so, it might be that they had some symptoms, it might be that they had family members that got cancer, and so on. That introduces the biases that plague all other observational studies.
It is medically possible (and maybe even advisable) to get a colonoscopy without sedation. It's uncomfortable but no more uncomfortable than any other... rectal insertion, and a non-negligible fraction of the population does that recreationally.
However, I've also had doctors commit medical assault by sedating me even after I explicitly withheld consent, so be careful where you go and consider, idk, taking along an overzealous prosecutor or something. There's not much that can be done about medical assault.
I was a little surprised that sedation was part of it at all. I wasn't prepared for that, and I tend to hate it. But this one was one smooth as silk compared to the other times I'd been put under.
I'm really sorry to hear about your doctor not respecting your wishes on that.
I was sedated, but it was literally a sedative. I was not put under. The only discomfort I had was a pain when they were taking a bend. Because I wasn't put under I was able to tell the nurse what was going on and she work her hands around my guts to ease the scope in making the turn. No problem. They even had to do a biopsy - and I didn't feel a thing.
>It's uncomfortable but no more uncomfortable than any other... rectal insertion....
What? What other... rectal insertion extends FIVE FEET, the length of the colon?
I'm an anesthesiologist (x 38 years; retired) present for scores of colonoscopies during my career. Occasionally patients requested zero sedation and I ALWAYS agreed.
I asked each time, explicitly: if you're so uncomfortable the procedure can't be completed — which happens, including to me the each time I've had a colonoscopy — do you want it to stop so you can return another day after a new prep, or do you agree to being sedated enough to proceed? 100% of patients (including me) agreed to sedation if needed.
You would have been my very first patient EVER to have had the procedure cancelled.
Note that every time I have a colonoscopy (I've had four, every five years, and have #5 scheduled on February 3, 2023 [I'm 74 years old and if this one is negative it will be my last one ever, as risks after age 75-80 exceed benefits]) I request zero sedation — heck, I know the risks better than anyone, after all — and every time I simply can't take the discomfort/pain.
Sounds like you had doctors performing the procedure who have gotten sloppy because most of their patients are too sedated to tell that the procedure is being done incorrectly and unsafely. As you know perfectly well, the colon doesn't have that many sensations available to it. I've watched a biopsy being taken and been able to feel nothing (which is itself uncomfortably surreal). I suspect discomfort mostly comes from the doctor forcing the scope around bends rather than guiding it. Again, it's not supposed to be comfortable but when done properly the discomfort should mostly be localized to the rectum and the usual sensation of pressure/urge for bowel movement that accompanies any insertion.
If we didn't have the major butt stuff taboo in our society, it would be most efficient for rectal insertion aficionados to be recruited during training of physicians for this procedure, as they could reliably inform the physician whether the procedure was causing safe or unsafe discomfort.
I am gratified to hear yet another anecdote of doctors themselves choosing to go with no sedation, which matches the research I did when I chose to start requesting that way myself. Maybe you should also be concerned with the disparity in how that request was initially met, between a "fellow doctor" and "stupid patient what does he know, let's sedate him anyways". And get a better gastroenterologist.
I’d like to thank both of you and the GP for posting this. As someone getting older, it’s important to know things like requesting no sedation is even an option. I’m much more concerned about damage deeper in than any potential discomfort “at the exit” … I’ve eaten some questionable food in my life and experienced a surprisingly diverse set of gastrointestinal sensations as a result… and the very idea of a doctor being sloppy with the technique pushing something backwards past those “corners, due to the majority of patients being sedated and not noticing, is genuinely giving me more mental discomfort than any sensation my guts ever had.
Thank you both for the frank and valuable comments. Also I think you have an interesting point about the “volunteers”/“recruits” thing. I suspect it’s less of a taboo about butt stuff and more that the procedure has some small risk of a potentially very serious complications (bowel perforation is serious business) and therefore should never be done on a person unless necessary… which is a noble idea but it does have potential repercussions like the current scenario where lack of non-sedated patient feedback leads to sloppy technique which arguably increases the risks of bowel perforation… sort of creates a vicious cycle that doesn’t help minimise patient risk.
I’m also finding it amusing trying to think about how they could thread the ethical needle on this if they ever tried such a thing. Any obvious sexual paraphilia that involves wanting to get the procedure done is sort of going to make the medial consent forms a little hard to rely on due to it being perilously close to knowingly performing a sexual act on them. Ive had a pretty good chuckle pondering legalese variations of “you swear that you are ok with having long objects inserted into your rectum and this is in no way a sexual fetish”.
While the prep for a colonoscopy is inconvenient, the actual procedure is not really a bother at all. As someone over 50, I’ve never had problems with insurance to authorize it.
One thing I fail to understand is the extraordinary difference of time span between such tests, in the US vs France (for example). In the former I got a "come back in 10 years", in France I'm being advised to have it every two.
If you are of an age where a colonoscopy is suggested as part of your physical exam, I'd suggest considering the stool DNA test. I just recently had this conversation with my doctor and he felt that the DNA test now has a sufficiently low false negative rate that it is an acceptable substitute. You only go on to get a colonoscopy if the DNA test is positive. False positives do happen.
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[ 0.21 ms ] story [ 55.5 ms ] threadBut if you just compare the people who SELF SELECTED themselves to undergo the trial then you introduce the biases that you attempted to overcome by using a randomized controlled trial.
Screenings result in false positives and in complications. One has to show rigorously that screening has net benefits.
I thought we have learned our lesson from the PSA fiasco.
Their main criticism of the study is this:
> If the compliance rate had been 100%, the researchers’ analysis showed, the test would have reduced cancer risk by 31% — from 1.22% to 0.84% — and it would have reduced the risk of death from colorectal cancer by 50% — from 0.3% to 0.15%.
But the study did no such thing. There's no way for the study to do such a thing.
What they describe is the comparing the results on the SELF SELECTED group of those who decided to go and get screened. This is no longer a randomized controlled trial.
We have no idea why those who decided to get screened did so, it might be that they had some symptoms, it might be that they had family members that got cancer, and so on. That introduces the biases that plague all other observational studies.
The worst part was trying to get my insurer to pay for it.
However, I've also had doctors commit medical assault by sedating me even after I explicitly withheld consent, so be careful where you go and consider, idk, taking along an overzealous prosecutor or something. There's not much that can be done about medical assault.
I'm really sorry to hear about your doctor not respecting your wishes on that.
What? What other... rectal insertion extends FIVE FEET, the length of the colon?
I'm an anesthesiologist (x 38 years; retired) present for scores of colonoscopies during my career. Occasionally patients requested zero sedation and I ALWAYS agreed.
I asked each time, explicitly: if you're so uncomfortable the procedure can't be completed — which happens, including to me the each time I've had a colonoscopy — do you want it to stop so you can return another day after a new prep, or do you agree to being sedated enough to proceed? 100% of patients (including me) agreed to sedation if needed.
You would have been my very first patient EVER to have had the procedure cancelled.
Note that every time I have a colonoscopy (I've had four, every five years, and have #5 scheduled on February 3, 2023 [I'm 74 years old and if this one is negative it will be my last one ever, as risks after age 75-80 exceed benefits]) I request zero sedation — heck, I know the risks better than anyone, after all — and every time I simply can't take the discomfort/pain.
If we didn't have the major butt stuff taboo in our society, it would be most efficient for rectal insertion aficionados to be recruited during training of physicians for this procedure, as they could reliably inform the physician whether the procedure was causing safe or unsafe discomfort.
I am gratified to hear yet another anecdote of doctors themselves choosing to go with no sedation, which matches the research I did when I chose to start requesting that way myself. Maybe you should also be concerned with the disparity in how that request was initially met, between a "fellow doctor" and "stupid patient what does he know, let's sedate him anyways". And get a better gastroenterologist.
Thank you both for the frank and valuable comments. Also I think you have an interesting point about the “volunteers”/“recruits” thing. I suspect it’s less of a taboo about butt stuff and more that the procedure has some small risk of a potentially very serious complications (bowel perforation is serious business) and therefore should never be done on a person unless necessary… which is a noble idea but it does have potential repercussions like the current scenario where lack of non-sedated patient feedback leads to sloppy technique which arguably increases the risks of bowel perforation… sort of creates a vicious cycle that doesn’t help minimise patient risk.
I’m also finding it amusing trying to think about how they could thread the ethical needle on this if they ever tried such a thing. Any obvious sexual paraphilia that involves wanting to get the procedure done is sort of going to make the medial consent forms a little hard to rely on due to it being perilously close to knowingly performing a sexual act on them. Ive had a pretty good chuckle pondering legalese variations of “you swear that you are ok with having long objects inserted into your rectum and this is in no way a sexual fetish”.