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Virtual Colonoscopy Can Spot Cancers Outside Colon


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Virtual Colonoscopy Can Spot Cancers Outside Colon

Our Review Summary

Based on a news release.

No independent expert perspective.

Numbers that inflated the supposed benefit and hid the possible harms. 



Why This Matters

Add this story to the pile of hype that has accumulated to support newer virtual colonoscopy despite the hidden but even higher piles of evidence raising legitimate questions about its expanded use.  This story did not serve the public good.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

No discussion of cost of virtual colonoscopy.  And, since a conventional colonoscopy must still be performed if abnormalities are found, the costs quickly mount in the face of anything suspicious.  But remember: this story was about abnormal findings outside the colon – 76% of which were found to be insigificant.  But we weren’t given any estimate of the significant costs expended to show that 76% of these findings were insignificant.

How can you NOT discuss cost in the context of this story? 

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The quantification that was given – the 78% increased odds of identifying high-risk lesions" – was not at all helpful, for reasons we described in the "evidence" criterion above. 

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

There wasn’t a word about a downside, a disadvantage, a harm of virtual colonoscopy.  In the use in question, 76% of people might consider it a harm that a test that suggested a problem outside the colon were actually told this was an insignificant finding. 

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

Fun with numbers.

The story says that 2,277 people had a virtual colonoscopy. Cancers and lesions outside the colon were identified in 1,037 patients – 787 insignificant and 240 significant. That means 76% were insignificant. But it also means that 10% of those who had the scan were found to have significant lesions.

The story didn’t provide those percentages.

But it did provide the unexplained stat that "virtual colonoscopy increased the odds of identifying high risk lesions by 78%."  Where do those numbers come from? 

A story on MedPageToday explained where that number came from when it said, "CT colonography detected 16 high-risk lesions, whereas nine would have been identified by optical colonoscopy, resulting in a 78% increase in the yield of high-risk lesions." 

So, remember, you’re using this technology on 2,277 people in order to find 7 high-risk lesions that would not have been found by traditional colonoscopy. 

This story could not have failed much worse in explaining the evidence.

Does the story commit disease-mongering?

Not Satisfactory

The subhead – in what it says and in what it doesn’t say – is disease-mongering, in our view.  It says that that the "less invasive procedure raises chances of finding high-risk lesions."  But it raised the chances much higher of finding what were termed "insignificant" lesions.  Why wasn’t THAT in the headline? 

The implication to readers is, "Run out and get a virtual colonoscopy – you need to find these high-risk lesions!"

The fact that 3 out of 4 findings didn’t need to be found – and the fact that the subhead and the story don’t emphasize that – is disease-mongering.  

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

There was no independent source used to scrutinize the claims made. 

Does the story compare the new approach with existing alternatives?

Not Satisfactory

The story sets up an uneven playing field at the outset by framing virtual colonoscopy as able to identify colorectal cancer, boost the likelihood of detecting cancers outside the colon, as less invasive, and as an option to be a "onetime procedure to identify significant treatable intracolonic and extracolonic lesions." 

But the information on the link to the National Cancer Institute which the story provides spells out clearly:  "The doctor cannot take tissue samples or remove polyps during VC, so a conventional colonoscopy must be performed if abnormalities are found. Also, VC does not show as much detail as a conventional colonoscopy, so polyps smaller than 10 millimeters in diameter may not show up on the images."

So the "onetime procedure" idea is false.  If trouble in the colon is found, it’s at least a dual procedure – VC followed by traditional colonoscopy.
And that kind of shoots holes in the less invasive idea as well. 

So there was no meaningful comparison made in this story.  It was a slam dunk for virtual colonoscopy, from a single source, promoting his findings, unchallenged by any independent expert.

Does the story establish the availability of the treatment/test/product/procedure?

Not Satisfactory

An assumption is apparently made that all readers know the availability of virtual colonoscopy, because the topic is never addressed.

Does the story establish the true novelty of the approach?

Not Satisfactory

The journal article itself stated, "Prior studies have suggested that these extracolonic findings are clinically significant in 10% to 23% of cases, the authors wrote in their introduction."  But this story gives us no indication that there had been prior studies on this topic.

Does the story appear to rely solely or largely on a news release?

Not Satisfactory

The story admits its quote of a study author came from a news release.  There is no evidence that anything else came from any independent reporting.

Total Score: 0 of 10 Satisfactory


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