As radiologists push for “virtual” colonoscopy coverage, risk of misleading readers is real

Claims from an ACR news release made their way into Baltimore Sun story on virtual colonoscopy. Credit Barbara Haddock/TNS

Claims from an ACR news release made their way into a Baltimore Sun story on virtual colonoscopy. Credit Barbara Haddock/TNS.

The American College of Radiology (ACR), together with the Colon Cancer Alliance and other advocacy groups, want you to know that they’re urging Medicare to cover seniors for “virtual” colonoscopy screening (also known as CT colonography).

Virtual colonoscopy is widely touted as an image-guided, less-invasive alternative to the standard colonoscopies that we’re all familiar with. The test was endorsed by recent guidelines from the U.S. Preventive Services Task Force (USPSTF) with an “A” rating. Now some groups are suggesting that it’s time for Medicare to start paying providers to administer these tests.

Here’s a quote from Eric Hargis, public policy adviser for the Colon Cancer Alliance, in an ACR news release:

“The best colorectal cancer screening exam is the one that a person chooses to use. Too many Americans are dying from a largely preventable disease that can almost always be treated if found early. Medicare coverage of virtual colonoscopy would ensure access to a proven screening method for those who cannot, or will not, have an optical colonoscopy. This will save lives.”

Before I unpack this quote, I want to be clear about what I’m not going to be commenting on in this post:

  • I’m not commenting on whether Medicare should or shouldn’t cover the test.
  • I’m not suggesting that the test doesn’t have legitimate advantages that may make it preferable to standard colonoscopy for some people.

What am I writing about then? The issue here is misinformation and overstatement of what this test is capable of. And the fact that exaggerated claims in this news release may mislead consumers and policymakers about the test’s effectiveness and its downsides.

First, colon cancer is far from ‘largely preventable’

The claim that colon cancer is “largely preventable” through screening was made three times in the release by Hargis and others. But this is not the case, says Richard Hoffman, MD, MPH, a screening expert and one of our long-time contributors.

“The best studies (randomized controlled trials) suggest we can reduce the risk of cancer by about 20%” with some types of screening, says Hoffman. “That’s hardly the same as being ‘largely preventable.'”

Second, virtual colonoscopy is not a replacement for the standard procedure

Then there is Hargis’s claims that virtual colonoscopy is a “proven screening method for those who cannot, or will not, have an optical colonoscopy.”

Hoffman notes that “If you CANNOT undergo optical colonoscopy then there is no point in undergoing CT colonography because positive results require diagnostic evaluation with optical colonoscopy.”

In other words, if the virtual colonoscopy finds a polyp that needs to be removed, it will take an additional, standard colonoscopy to go in there and get it.

Even Hargis’s claim, lower down in the release, that virtual colonoscopy can “overcome cultural stigmas” about colon cancer screening plays to misconceptions about the “virtual” nature of test. As Hoffman points out, the test still requires patients to have a very real tube inserted in the rectum so that the bowels can be inflated and imaged. Colonoscopy’s notorious pre-screen bowel cleanse is also a requirement for the virtual alternative.

Hoffman says, “We published a study suggesting that some Mexican-American men were worried that colonoscopy could transform their sexual identify. They preferred fecal blood tests [a different form of colon cancer screening]. It’s not clear that CT colonography would be much less stigmatizing. The bowel prep is also similar.”

Third, claiming that virtual colonoscopy is “lifesaving” is shaky ground

Perhaps most importantly, there’s Hargis’s bold claim that virtual colonoscopy will “save lives,” which is repeated in some variation four times throughout the release.

The problem? As Hoffman told me, “no clinical trial has demonstrated that CT colonography saves lives.”

Indeed, the USPSTF recommendations for CT colonography are based on modeling studies that extrapolate benefits for various forms of colon cancer screening from surveillance data. Only stool blood tests and flexible sigmoidoscopy (in which a flexible tube with a camera is used to view only the lower part of the colon rather than the entire colon as with a standard colonoscopy) have been shown to reduce colon cancer mortality in clinical trials. No direct evidence from a trial has ever shown that CT colonography, or even a standard colonoscopy, produces the same benefit.

What’s more, even if these screening methods are found to reduce colon cancer mortality, that doesn’t necessarily mean that screened people live any longer than they would have otherwise. As a National Cancer Institute evidence summary points out,  “Based on solid evidence, screening for colorectal cancer (CRC) reduces CRC mortality, but there is little evidence that it reduces all-cause mortality, possibly because of an observed increase in other causes of death.”

Is your life “saved” if screening leads to early identification and treatment of a colon tumor that might never have killed you — and yet you end up dying earlier from an infection or heart attack that was hastened by the cancer radiation or chemotherapy? That’s what some evidence suggests could be happening.

It might also be that studies just haven’t been large enough to detect the small benefit that screening confers on overall survival.

Whatever the case, the idea that any form of colon cancer screening leads to a longer life simply hasn’t been borne out by high-quality research.

Does the average consumer understand this? Do they know that there are important tradeoffs and uncertainties surrounding colon cancer screening? Such nuance has been largely drowned out by a media chorus of uncritical pro-screening messages, most of which focus on the benefits of colonoscopies.

Why do the claims made in a promotional news release matter?

This matters because the claims originating in this news release were repeated to countless readers by major news outlets across the country. For example, this Baltimore Sun story that references the news release was picked up by other TRONC-owned news outlets ranging from the Bend Oregon Bulletin to the Miami Herald, which headlined the piece, New colonoscopy technique may save your life with less indignity and discomfort.

The story frames the issue in the favorable light suggested by the ACR news release, and it leads with an anecdote from a patient who says her experience, which she described as “easy” and “painless,”  turned her into “an advocate” for the procedure. She’s also featured in a video that accompanies the story.

We’ve discussed in considerable detail why such single-anecdote stories are problematic.

Troublingly, Hargis’s “lifesaving” quote from the ACR news release also ran in these stories without any direct challenge.

What did the Sun story get right?

The Sun story deserves praise, however, for going well beyond the news release in other areas and bringing some important context to the issue.

It notes that  “not all doctors believe virtual colonoscopies should be used in place of the traditional procedure.” This includes Dr. Anurag Maheshwari, a gastroenterologist quoted in the story who explains,

“If you find polyps through the virtual procedure, a second procedure would have to be done to remove them. Polyps can be removed during a traditional colonoscopy.”

And the Herald headline notwithstanding, the story also suggests that the procedure might well involve some “indignity” and “cultural stigma.”

For a virtual colonoscopy, a small flexible tip is placed just into the rectum to inflate the colon so an MRI or CT scanner can be used to look at the colon and rectum. Patients still must clean their systems out but need not be sedated.

What could the Sun story have done better?

  • It would have been helpful to dig deeper into the evidence supporting virtual colonoscopy and where the claims of “lifesaving” benefit come from. While the virtual test seems to be pretty good at finding polyps, it’s unclear if it can save lives and it’s misleading to state that it does.
  • The story should have included a more thorough discussion of harms that can result from virtual colonoscopy. The USPSTF notes that this test turns up “extracolonic findings” (sometimes referred to as “incidentalomas”) in 40% to 70% of screening tests — a smaller percentage of which require additional follow-up. This can lead down a rabbit hole of additional tests and procedures for what may turn out to be benign growths in other parts of the body. The guidelines state that “evidence to bound the potential harms of this technology is still lacking, particularly in regard to incidental findings.” These potential harms include “additional diagnostic testing of an abnormality that is of no clinical importance, as well as treatment of findings that may never threaten a patient’s health or even become apparent without screening (ie, overdiagnosis and overtreatment).”
  • The story should have provided the commercial context for the news release and the fact that there are conflicts of interest at play. The colonoscopy market by some estimates is worth more than $10 billion annually in the United States, and the radiologists who perform virtual colonoscopies may hope to wrest some of that huge market from gastroenterologists who perform traditional colonoscopies. Similarly, Hargis’s Colon Cancer Alliance counts among its sponsors a host of drug and device companies, including  The Medical Imaging & Technology Alliance (MITA), which bills itself as “the collective voice of medical imaging equipment manufacturers.” Those relationships could certainly color his thinking on the value of imaging-guided colon cancer screening.
  • The single patient voice in the story could have been supplemented with other perspectives. Imagine what a difference it would have made to hear from someone whose virtual colonoscopy found suspicious spots outside the colon that led to additional unnecessary tests and procedures. Such a perspective is recounted in harrowing detail by a radiologist to his colleagues here. He concludes: “What is often missing from radiologists’ thoughts is firsthand experience with the clinical drama that follows screening or diagnostic tests.”

So here’s a recap:

Advocacy groups and professional organizations have every right to argue on behalf of procedures that they believe are beneficial, and virtual colonoscopy does indeed have certain advantages over its standard counterpart.

However, advocacy groups — and certainly physician groups — should not overstate or exaggerate the benefits of such procedures in ways that may mislead consumers and policymakers.

Journalists should refrain from repeating exaggerated claims from news releases in their stories, and should directly challenge such claims if they must be repeated.

Claims about health interventions should always include a thorough explanation of the supporting evidence and potential harms, as well as mention of the potential conflicts of interest that may influence the perspective of those making the claims.

Our list of criteria for health news stories discusses these and other components of quality health news in detail.

You might also like


Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.

Comments are closed.