Virtually no news about virtual colonoscopy questions


Newer is not always better. Evidence is important. Simple themes, oft forgotten in health journalism.

Back in October, an Atlanta Journal-Constitution story talked of the wonders of virtual colonoscopy, saying it replaced the dreaded colonoscope and lessened patient risk. It used these words to refer to the technology: "science fiction, Star Wars, video game, Disney World."

AJC virtual colonoscopy.png

Also in October, the Wall Street Journal promoted the growing popularity of virtual colonoscopies.

WSJ virtual colonoscopy.png

Neither story mentioned the fact that the U.S. Preventive Services Task Force had stated that same month that "The evidence is insufficient to assess the benefits and harms of computed tomographic colonography as a screening modality for colorectal cancer."

Last week's announcement that Medicare may stop paying for virtual colonoscopies also got little news attention. At least the New York Times reported it. Excerpts:

The Centers for Medicare and Medicaid Services said in a decision posted on its Web site that there was "insufficient evidence" to conclude that virtual colonoscopy "improves outcomes in Medicare beneficiaries."

...the United States Preventive Services Task Force, which advises the government on prevention, said last year that there was insufficient evidence to assess the benefits and harms of the CT technique. Some private insurers pay for the tests; others do not.
In its analysis, Medicare said many studies supporting virtual colonoscopy were done in people with a mean age around 58, so results might not fully apply to Medicare's older population.

For instance, older people are more likely to have polyps. So the proportion of people who would have to have a conventional colonoscopy after a virtual one would be greater. That would make the CT scan less cost-effective.


Virtual colonoscopy has a role in those individuals who because of anatomical obstructions, such as adhesions, preclude the standard approach. However, a recent report in JAMA showed that 1 in 1200 recipients of a CAT Scan have a significant increase in radiation induced disease. One has to always weigh the risks and benefits of any medical decision.

Why don't people ever mention that a virtual colonoscopy requires an enema? The idea that it is "less invasive" doesn't equate with "it's more comfortable." Here is a description of the procedure from the National Digestive Diseases clearinghouse website:
How is virtual colonoscopy performed?

Virtual colonoscopy is performed wherever the CT scanner or MRI unit is located—usually in the radiology department of a hospital or medical center. The procedure takes about 10 minutes and does not require sedation.

* Patients will lie face up on a table.
* A thin tube will be inserted through the anus and into the rectum. For CT, carbon dioxide gas will be pumped through the tube to expand the large intestine for better viewing. For MRI, contrast media will be given rectally to expand the large intestine.
* The table will move through the CT scanner or MRI unit to produce a series of cross-sectional images of the colon.
* At various points during the procedure, the doctor may ask patients to hold their breath to steady the images.
* The procedure will be repeated while patients lie face down.

Um....I think I'll drink the jug and be sedated for the colonoscopy, thank you.

About this Entry

This page contains a single entry by Gary Schwitzer published on February 15, 2009 9:28 AM.

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