The actual study is titled "Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death" [1]
The authors conclude that "In this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening. "
I find it generally more useful link to the (abstract) of the original article, rather than second hand news reports. The abstracts are usually pretty accessible for a somewhat technical audience, they're not written for domain experts only. As we see in the discussions here, it's questionable whether the rephrasing from journalists really adds anything.
Like, for example, how it is called the “gold standard” because it’s a 10-year large scale randomized trial, and the doctors running the study are the ones who promoted colonoscopy as a tool to reduce cancer mortality in the first place.
The study answers a question pertaining public health policy (should we invite everyone in some age group for a colonoscopy?). It does not answer any individual health/treatment/screening question. The article's headline and content is problematic because it's easy to confuse the two, and the vast majority of readers will never get involved in public health policy (but will certainly have to make lots of individual health decisions).
"Study failed to find a reduction" _does not equal_ "There wasn't a reduction".
From the abstract: "The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16)"
Look at the confidence interval. This study was both consistent with a 36% reduction in deaths or a 16% increase in deaths. It's just a really wide range. All we can say about this study is that it didn't gather enough data to identify the size of the effect, not that there wasn't an effect.
This is likely because there wasn't that many people who died of colon cancer in any of the groups. This study just didn't track enough people to provide an answer.
Cancer is much more treatable, these days.
I had a friend that just underwent seven months of chemo for colorectal cancer. Looks like he'll be fine, but it was Stage IV, when it was discovered. Had a couple of surgeries, and radiation. The chemo was the worst, though. He channeled Uncle Fester, and this was a fairly robust, somewhat overweight chap.
So he would not go in the "death" column, but I guarantee that he would not be one to dismiss the seriousness of the disease (or its treatment).
This isn’t true. The secondary analysis shows a reduced death rate.
The problem with the title is that it says “Effect of Colonoscopy Screening”, not “Effect of telling people to get a colonoscopy screening”, where the primary analysis is making conclusions based on the latter.
Maybe this style of title is standard for medical journals, but the argument in this thread is based on the title priming us for what the paper is talking about, and directly leading to confusion.
Maybe you didn't read the article all the way through?
What it found was it merely inviting people to a colonoscopy did not result in less deaths from colon cancer, although it did result in fewer people being treated for it.
However, if you look at the people who actually took a colonoscopy, there was a 50% reduction in deaths from colon cancer.
That's not nothing.
But the risk of colon cancer did decrease, with a risk reduction of 18%.
Maybe they just didn't track long enough to tease out a bigger risk reduction in overall mortality, or maybe colon cancer is associated with other risk factors for mortality (like age).
Why someone would latch onto one result and not the other is probably just "blow the lid off" style reporting.
Argueing about the randomization of these numbers, and the meta-statistical aspects of that, would be funny if the subject wasn't so serious. It is also the same level of discussion you get from people like JBP, meaning it at least misses the point by a mile.
If the second-hand news report is well done, it should give you more context on the matter, and so be more useful than the "raw" abstract.
It does show quite nicely how one can lie through scientific studies and confuse people.
I’m really confused by this data. First of all, are they testing the efficacy of colonoscopy or the efficacy of inviting people to colonoscopy?
And then how is the former group’s reduction in deaths 50% and the latter group’s is about 0%?
This could also be true for the colonoscopy, that the more responsible/healthier people in the treatment group are more likely to get the colonoscopy and it's very possible responsibility/healthiness are driving the difference in health outcomes instead of the colonoscopy.
The control group was 50% of the population who didn't get an invitation.
The experimental group was 50% of the population who got an invitation for colonoscopy, but turned out to be subdivided into ~40% "health conscious" who actually followed up on the procedure, and ~60% who ignored it.
Presumably there's a corresponding ~40% "health conscious" component of the control group, but this experiment had no method for identifying them.
If the study only looked at that ~40% subset of the experimental group, as opposed to the entire group who received invitations, then they could no longer compare them to the control group.
I'm not sure what gold standard you are referring to (or the article or the paper - https://www.nejm.org/doi/full/10.1056/NEJMoa2208375).
Double blind studies require there to be data. An invitation doesn't speak to the effects of Colonoscopy screening at all, while simultaneously adding a confounding variable about participation. The data is about the effects of offering screenings, not the effect of those screenings, per se.
Lifelong data is the gold standard for questions about mortality and most Colonoscopy randomized trials started around 2010 (hence this very early 10-year study, which I would say is premature).
You're basicall saying "our randomization at the beginning of the trial is key to avoid biases, so we can't reassign people from the treatment group to the other group, even if they practically don't get the treatment". The reason is if you allow people to switch, your assignment is no longer random. People who avoid the treatment may have different health properties than the ones who don't.
In essence, you need your trial to be robust and large enough that a few people not getting the treatment don't matter.
Also I’m not sure if the article mentioned this, but the data seems to imply that the % of people who opted to get a colonoscopy was similar in the invited and control group.
So I'll still get my colonoscopy, thanks
When everyone who got a colonoscopy is compared to the control group 30% fewer got colon cancer 50% fewer people died of colon cancer
This data makes me think the mortality reduction benefit is bogus, but the cancer prevention benefit is real, and probably greater than 18%, maybe closer to 36-40%. If the colon cancer mortality benefit was real you'd see some reduction in the intention to treat group, and it'd be smaller than the cancer prevention effect. (The most aggressive cancers tend to be harder cancers to catch in time because they most so quickly, so most cancer screening tests will prevent more cancers than deaths)
> After 10 years, the researchers found that the participants who were invited to colonoscopy had an 18% reduction in colon cancer risk but were no less likely to die from colon cancer than those who were never invited to screening.
This seems to imply we should discount all treatments because people who choose to get treatment are more likely to get better, coincidentally by the same amount as the treatment's efficacy.
If you do medicine for profit and are allowed to advertise and market, doing more is always better.
I call that solid evidence which could potentially save millions of real lives.
We care about all-cause mortality, not cancer mortality.
https://www.respectfulinsolence.com/2022/07/27/john-ioannidi...
https://stevekirsch.substack.com/p/how-david-gorski-defends-...
Remember: you’re not being paranoid, if they are actually out to get you.
A colonoscopy is quite unpleasant; you starve for a day, and take an enema. They may sedate you before the procedure. If they don't, then the procedure is quite uncomfortable; not exactly painful, but unpleasant.
Incidentally, if they find and remove a polyp, they will plant a tattoo inside your gut to mark the spot, for the benefit of future spelunking visitors.
fast for a day, starvation is another thing and takes weeks to set in for the average westerner
I was sedated, so laxative was the hardest part of the ordeal, not the fasting or actual procedure.
I wouldn't describe it as "extremely awful". It was very uncomfortable; I'd compare it to 40 minutes of dental hygiening.
I think it's nuts that they use this procedure for screening. I'm screened for bowel cancer annually, using a fecal sample pack they send me through the post, and that I post back. No hospital visit, no treatment room, no expensive equipment, no nurses and doctors. The only reason I can think of for using colonoscopy as a screening technique is that it's costly.
I personally know 4 people who had the procedure and cancer was detected. Some further along than others. All still living.
Colonoscopy is one of the few procedures that as they screen they can also take action.
Not all cancer is the same.
Every person will have some amount of cancer as they get older. Some of the cancer will not be aggressive or disruptive enough to cause a problem before the person dies of another old-age related infirmary.
Treating cancer is not free. Treatment reduces the quality of life of the person treated. Elderly people are slower to heal, and more at risk for complications. To treat a cancer that would not cause problems in the natural lifespan of its host is an expensive mistake.
Screening technology can expand our ability to detect cancer without giving us the insight to know dangerous cancer from inconsequential cancer. When we go on to treat inconsequential cancer we've actually reduced the years of healthy life of the patient.
Sadly my oldest brother didn't catch his so quickly and the colonoscopy he had showed he was pretty far along, and ultimately the cancer spread and killed him.
I now have one every 5 years until I hit 50 then I'll move to every 2 years. The test is pretty pain and issue free, the only 'bad' part if the laxatives first, but after seeing my brother die, it is well worth the couple of hours of discomfort.
My older brothers had continued with faecal testing, but after some pushing moved to colonoscopies too, as we'd rather catch it early, than once it has taken hold.
5/1000 colonoscopy patients have complications (some fatal) which is way higher than the base rate for colon cancer.
It’s not a harmless screen like a mammogram.
Can you provide a source for this?
A very interesting related study has become known as "The Norwegian Colorectal Study" found that early testing was a waste of money since only those with a family history of colorectal cancer or IBS symptoms or both actually got colorectal cancer before 55. For most people the polyps which are precursors to colorectal cancer do not appear before age 55. That means that the current push for aggressive testing starting at 50 is a distracting waste of time, money, and effort that should be eased back.
IIUC, there was still a reduction in colon cancer deaths, but the populations still experienced the same % of deaths from all causes.
After all the debate here in HN about the interpretation of the data and the statistics, I'm really looking forward to see a post in 15 years with the new study.
All the study really proves is that offering someone a colonoscopy isn't the same thing as giving them one.
Perhaps it was oversold, but a 20% reduction still seems significant.
> please use the original title, unless it is misleading or linkbait; don't editorialize
I'm finding myself disappointed with the application of guidelines here. The title has been changed to a completely made up headline, differing from the original, which is editorializing. It's the second time this happens in the past 24 hours - yesterday the ".. you idiot" part was removed from a blog post completely numbing the post's intention. Neither was misleading or clickbait.
EDIT: while typing this comment, the title has been changed yet again to reflect the paper's title "Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death".
The article here just looks at cancer mortality, which is not what anyone should care about.
For more recent commentary, an example is https://blogs.scientificamerican.com/cross-check/why-i-wont-...
Here some videos (may be NSFW):
https://www.youtube.com/watch?v=B1LREA1ZuUE
But there are lots more to see.
I believe what he discovered is important. Not that I believe his advice to drink ionized water (Kangen water) is scientifically sound. But that does not matter for the discovery that switching to eat rice and veggies cleans your intestine.
Don’t be so afraid of death. It’s not that bad. Really.
Source: survived an NDE. Was not my time was told, but did get a great tour of the afterlife. Don’t worry so much.
And treat strangers with kindness, they were very insistent on that. They keep score. Heaven or Hell. It’s your decision.
:-)
So, kind of like how pruning a plant does not necessarily weaken it.
Possible reasons I thought of:
- cancer cells metastasize/spread much earlier than we previously thought (https://www.statnews.com/2016/12/14/cancer-cells-spread-meta...)
- what if the presence of polyps is not all bad? i.e. maybe they keep the immune system in a tumor-responsive state, or they locally deplete nutrients that would otherwise feed other pre-cancerous cells?
The Japanese have a higher colon cancer rate, what percent die there?
Looking for death vs no-death alone as an outcome for medical diagnosis/treatment is short sighted.
* Colonoscopies reduce incidence of colon cancer but apparently not death from colon cancer.
* This is probably because colon cancer therapies are good, so even if you get colon cancer your prognosis is good.
* The take-away is not that colonoscopies reduce your chances of death, but that they reduce your chances of having to suffer colon cancer and subsequent therapies. That might still be a good trade-off.
surely your risk can be further reduced by having annual colonoscopy if you are in the high risk group, e.g. with family history.
