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Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

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Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#181

Post by sokoloff »

thaumasiotes wrote: post #177
sokoloff wrote: post #166

Earlier quoted context omitted.

You can control for the invitation vs no-invitation and colonoscopy vs no-colonoscopy and analyze the outcomes of all four cells (provided you have enough people in each cell) or the column or row independently.

You can do that, but you won't learn anything, because the populations within each cell are not comparable to each other.

It seems to me with electronic medical records that you could do population-wide studies using data that already exists (and I think that would pass IRB, or at least "ought to"). That would likely tell you "for the patients matching criteria X (are covered by BCBS and live in state X, or whatever), the 10 year outcome for patients who turned 50 in 2010 was Y vs Z conditioned on whether they had a colonoscopy".

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#182

Post by JoeAltmaier »

timr wrote: post #174
JoeAltmaier wrote: post #165

Earlier quoted context omitted.

1 in 1000 have complications. Colon cancer attacks 1 in 25. So that math check out - have your colonoscopy

> Colon cancer attacks 1 in 25. The highest plausible 10-year estimate of colon cancer prevalence from the study was 1.2%. That's 1 in 83, not 1 in 25.

Not what I saw on another site, but yours is more recent so ok.

Still a long way from 1:1000

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#183

Post by denton-scratch »

doliveira wrote: post #145
denton-scratch wrote: post #52

This is about colonoscopy screening . If you give a fecal sample and it comes up as suspicious, the next step will be a colonoscopy anyway. 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 ta…

Wow, colonoscopy with no sedation must be extremely awful. Isn't sedation the default anywhere? I remember the papers I had to sign were really serious about advicing sedation.

I couldn't be sedated, because I had no companion to take me home, and a taxi doesn't cut it.

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.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#184

Post by pbourke »

JamesBarney wrote: post #20
pbourke wrote: post #15

Earlier quoted context omitted.

In this case they are examining colon cancer and deaths from it, and the colonoscopy is a diagnostic test for colon cancer. I feel that the results are being presented to the public in a very misleading way. People will read this headline and conclude that they don’t need to get a colonoscopy which I don’t think follows from this study at all.

The study results are "colonoscopies do not lead to a reduction in colon cancer mortality". Reporting that isn't misleading that's what the study says. Basically in the treated group of 1103 of every 10,000 people died. And in the control group 1104 of every 10,000 people died. So to summarize the study. Inviting someone to a colonoscopy reduces their risk of getting colon cancer by 22 basis points. Their risk of dyi…

> The study results are "colonoscopies do not lead to a reduction in colon cancer mortality". Reporting that isn't misleading that's what the study says.

The measured intervention was not the colonoscopy, it was the invitation to screen. Only 42% of invited patients actually got a colonoscopy. This is far more persuasive to me:

> "When the investigators compared just the 42% of participants in the invited group who actually showed up for a colonoscopy to the control group, they saw about a 30% reduction in colon cancer risk and a 50% reduction in colon cancer death. “That adds to a bunch of observational study data that suggests exposing people to colonoscopy can reduce risk of developing and dying of colon cancer,” Gupta said."

As a member of the public, I don't really care about invitation to screen, but do care about the efficacy of colonoscopy. I can see invitation to screen being an important concern from a public health standpoint.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#185

Post by readthenotes1 »

ricardobeat wrote: post #29
em500 wrote: post #27

Several posters have criticized the title of the news article "In gold-standard trial, colonoscopy fails to reduce rate of cancer deaths". 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 colono…

There is nothing wrong with the title. The study failed to find a reduction in death rate despite lowering the incidence of cancer, and that is the center of the piece. It goes into detail of why this is surprising. The study authors were interviewed and agreed. The reporting actually adds a lot of context that you would never get from a link to a random study. Like, for example, how it is called the “gold standard”…

"The study failed to find a reduction in death rate despite lowering the incidence of cancer, and that is the center of the piece"

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.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#186

Post by eecc »

pessimizer wrote: post #100
eecc wrote: post #92

Earlier quoted context omitted.

Well then the title is indeed misleading. It's not the colonoscopy that's failing to reduce cancer death rates, treatments are. Indeed the title should have been: with colon cancer deaths unchanged, screening and pre-malignant treatments are ever more important.

This is nonsensical. Any number of things are failing to reduce cancer death rates, including professional football and jelly donuts. This study is about colonoscopies also failing to reduce cancer death rates. Changing the title to Don't Worry About Colon Cancer Death Rates, Just Continue To Do What You're Told would not have been better or more accurate.

> This is nonsensical.

Can you please keep it civil and avoid devolving into insults? I don't spend my time online to get treated like a fool. Now please restrain yourself from trolling even further and say "well, then don't say foolish things" because I'd flag you.

If you bothered reading the article, a paragraph reads that this particular form of screening did have an impact. Just not as significant as the community thought.

The study is about _one particular form of screening_ that might might have been oversold. Perfectly consistent with the parent observation and my own: screening is significant, curing cancer isn't as easy as avoiding it altogether.

Now, if you have something constructive to add please do so. Otherwise, please shut up and move on to some Reddit sub.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#187

Post by pazimzadeh »

Findecanor wrote: post #37
pazimzadeh wrote: post #25

> If the endoscopist discovers a suspicious polyp, then it’s promptly removed, thus nipping the cancer before it spreads So, kind of like how pruning a plant does not necessarily weaken it.

When the polyp has been nipped, it is gone. If you have a colon with no polyps (left) in it, you should be safe from colon cancer for at least a decade (how long polyps take to develop from mutation into a tumour).

If that's the case, then why was there no difference in mortality in the study?

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?

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#188

Post by thaumasiotes »

sokoloff wrote: post #181
thaumasiotes wrote: post #177

Earlier quoted context omitted.

You can do that, but you won't learn anything, because the populations within each cell are not comparable to each other.

It seems to me with electronic medical records that you could do population-wide studies using data that already exists (and I think that would pass IRB, or at least "ought to"). That would likely tell you "for the patients matching criteria X (are covered by BCBS and live in state X, or whatever), the 10 year outcome for patients who turned 50 in 2010 was Y vs Z conditioned on whether they had a colonoscopy".

What would you be trying to learn from that? You're comparing unlike groups. You can't draw any conclusions.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#189

Post by ricardobeat »

benchtobedside wrote: post #111
ricardobeat wrote: post #76

From the HN guidelines: > 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…

This post was submitted with the following title from the original article per the guidelines: "In gold-standard trial, colonoscopy fails to reduce rate of cancer deaths"

Exactly. There was no need to edit.

Re: Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

#190

Post by imgabe »

em500 wrote: post #49
ricardobeat wrote: post #29

Earlier quoted context omitted.

There is nothing wrong with the title. The study failed to find a reduction in death rate despite lowering the incidence of cancer, and that is the center of the piece. It goes into detail of why this is surprising. The study authors were interviewed and agreed. The reporting actually adds a lot of context that you would never get from a link to a random study. Like, for example, how it is called the “gold standard”…

The problem with the title is that it might lead individuals to believe they shouldn't bother with getting a colonoscopy. You can't conclude that from this study at all. If your doctor recommends you to get one, you probably should. 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…

Do people really ignore their doctor's advice because they saw a headline? I'm sure there are some examples, but that can't be the norm. Obviously a colonscopy can still be indicated for an individual even if it doesn't help by doing it en masse for everyone. Specific symptoms could indicate a colonoscopy would provide more information and there are a number of other conditions where it would be used besides colon cancer.

I can't realistically see anyone saying "No thanks, doc, I'm not going to get that colonoscopy you recommended, because I saw a headline"

This trend of saying a thing is bad because you can imagine some unbelievably stupid person misinterpreting it and misusing it is getting out of hand. At some point people are responsible for their own decisions.

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