Virtual Colonoscopy Is Convenient. But Experts Disagree on Whether It's as Good as the Real Thing.
Tuesday, April 28, 2009
When Eric Rowe turned 50, the question was not whether the Washington lawyer would be screened for colon cancer, but how. His wife had undergone a colonoscopy, the gold-standard exam that costs about $1,500, but Rowe's internist recommended an alternative that was less invasive and expensive: a virtual colonoscopy, which uses three-dimensional images from a CT scan to detect benign polyps or cancers.
"It sounded good to me," said Rowe, pleased that he could schedule the $800 procedure for 7:45 a.m. at a downtown medical building. Unlike standard colonoscopy, generally performed under anesthesia, in which a long, flexible scope is inserted into the rectum and snaked through the large intestine to find and snip out polyps, the new procedure doesn't require a ride home or a day off. Rowe planned to be at his desk an hour or so later.
Invented 16 years ago by a radiologist who got the idea while playing video games on a flight simulator during advanced training at Johns Hopkins, virtual colonoscopy has become an increasingly popular alternative to standard, or optical, colonoscopy, which is typically performed by a gastroenterologist. Initially regarded as a high-tech novelty, the new procedure has in recent months received key endorsements as a first-line screening test from influential medical groups, notably the American Cancer Society, after several large studies found it to be effective at finding large polyps.
Like other mass screening tests including mammography, the overarching question is whether the benefits of virtual colonoscopy outweigh the risks.
Its supporters, many of them radiologists who read CT scans, tout virtual colonoscopy as a more palatable alternative that has the potential to boost low rates of screening. One of the most common and deadliest malignancies, colon cancer can be prevented -- or even cured -- if detected early. Currently about half of Americans over 50 are screened for the disease; some shun traditional colonoscopy, which is the only way to remove polyps, because of its invasive nature.
"This is a really good test that's going to find way more cancer than optical colonoscopy," said Mark Klein of Washington Radiology Associates, who has performed more than 1,200 virtual colonoscopies since 2002, Rowe's among them. "Is it perfect? No. But no test is."
The prospects for significant expansion of the procedure, which is covered by a growing number of insurance companies, have collided with a large and unexpected roadblock. In February, officials at the Centers for Medicare & Medicaid Services (CMS) announced a preliminary decision not to cover the procedure as a mass screening test for Medicare recipients.
CMS officials, who are scheduled to issue their final ruling May 12, cited reservations expressed by the U.S. Preventive Services Task Force, an independent panel of health experts, and concluded that there is insufficient evidence that virtual colonoscopy would benefit Medicare recipients. CMS cited concerns about radiation exposure and the number of patients who would require follow-up colonoscopies to remove polyps, as well as the inability of CT scans to reliably detect small or flat growths.
Medicare's decision has sparked a furious lobbying campaign. More than 40 members of Congress have signed letters urging federal officials to reconsider, and the dispute has split doctors in the same specialty: the American Gastroenterological Association favors Medicare coverage, while the American College of Gastroenterology does not.
In many ways, the debate mirrors some of the complexities inherent in overhauling health care, a top priority of the Obama administration. At issue is whether virtual colonoscopy will enhance quality or whether it is, in the words of one physician blogger, "a proxy for high-tech excesses."
"CMS made the right decision," said John Petrini, a Santa Barbara, Calif., gastroenterologist who heads the American Society for Gastrointestinal Endoscopy. Why, he asks, should patients undergo two tests when one is sufficient?
Klein disagrees. "They got it completely wrong," he said. "Some people will die from that decision, completely unnecessarily," because they won't get a standard colonoscopy.