By Eric Barnes, AuntMinnie.com staff writer

November 7, 2011 -- A large survey of patients who underwent virtual colonoscopy at three U.S. centers found high acceptance of the noninvasive exam, as well as a reluctance to undergo conventional colonoscopy among nearly one-third of screening patients, according to results presented at the 2011 International Symposium on Virtual Colonoscopy in Cambridge, MA.

A separate study presented at last month's meeting also indicates high confidence in the efficacy of virtual colonoscopy (also known as CT colonography or CTC) among referring physicians, although they had concerns over the prep and the potential need for a second test if polyps are detected.

"The findings tell us our survey respondents had a high level of satisfaction with VC and showed a preference for VC over optical colonoscopy when given a choice," said Dr. David Kim, associate professor of radiology at the University of Wisconsin (UW).

A good start at UW

In the context of the two surveys, Kim discussed the increasing willingness of physicians to recommend virtual colonoscopy over seven years at UW Hospital and Clinics.

The CTC screening program, led by Dr. Perry Pickhardt, began in 2004, spurred on by the success of his large Department of Defense study and a shortage of gastroenterologists that left a waiting list of 1.5 to 2 years for optical colonoscopy in the Madison area, Kim said. The agreement by three insurance carriers a year later to reimburse the exams didn't hurt the cause.

"We were doing a ton of them," Kim said of the nascent VC program, adding that there was little opposition to virtual colonoscopy among referring physicians because "the majority weren't aware of the program and didn't have an opinion one way or the other."

By 2008, however, volume had dropped by 30% to 40% when a couple of referring physicians moved away, and the core pool of residents around the Madison area had been screened, he said. A denial of screening reimbursement when the U.S. Centers for Medicare and Medicaid Services (CMS) decided not to pay for the exam nationwide in 2009 also reduced interest in the exam.

But with time and a push for broader colon cancer screening in Wisconsin, volume has increased again, and support among referring physicians is now more broad-based. Still, CTC represents only about 8% of colon screening exams at the institution, Kim said.

In the program's early days, the biggest complaint among referring physicians was when the detection of a significant extracolonic finding led to a telephone call to the primary physician to suggest that the patient needed to be examined for the finding.

Some complained that the call for follow-up ended up increasing their workload. "But the idea of emailing them changed the way they thought about it," he said. "With a phone call, they would have to write it down and remember it."

With email notification, the referring physician isn't interrupted, he or she can take care of the matter when time permits, and the ensuing follow-up with the patient actually makes doctors and patients more confident in the quality of care, Kim said.

Provider survey

A new provider survey to be unveiled this fall really shows growing support among referring physicians for CTC screening, Kim said.

The survey of hundreds of Midwestern primary care physicians, part of a larger initiative to improve healthcare delivery, found that both virtual and optical colonoscopy enjoy more than 90% support as effective colorectal cancer screening methods, while flexible sigmoidoscopy and stool tests enjoyed far less support.

By far the greatest reported barrier to virtual colonoscopy was the patient prep, cited as the top concern by more than three-fourths of providers, Kim said. Lack of coverage was cited by more than half as a barrier to CTC screening.

Meanwhile, the top reason for primary care physicians not recommending CTC to patients was fear of the need for a second exam. "This is actually not true," Kim said, since well under 10% of screening patients actually need a follow-up optical colonoscopy exam.

But the finding highlights the need to educate primary care physicians about the small likelihood that a second exam will be needed to remove polyps detected at CTC, he said.

Patient survey

Kim also discussed the results of one of the largest U.S. patient surveys to date that will be presented at this year's RSNA meeting in Chicago during the Wednesday morning gastrointestinal radiology sessions.

The survey of nearly 1,500 patients who have undergone virtual colonoscopy might be somewhat biased because it came from patients who decided on CTC screening from the start, but the results show deep support and acceptance of the noninvasive exam, Kim said.

Kim's colleague Dr. Dustin Pooler, a radiology resident and currently a researcher at UW, agreed to share the results early in an interview this week with AuntMinnie.com.

Pooler, Kim, and colleagues, including Pickhardt and Dr. Brooks Cash from Bethesda, mailed a total of 2,548 surveys and received 1,417 completed surveys for a response rate of 56%, he said.

The 12-question study probed the attitudes of patients who had undergone virtual colonoscopy in approximately the past two years at the UW health center (n = 837 completed surveys); the Walter Reed National Military Medical Center in Bethesda, MD (n = 300 surveys); and the Colon Health Center of Newark, DE (n = 280 surveys), Pooler said.

"We didn't offer any incentives to complete the survey, and there was no follow-up phone call or second survey; this was just a one-time mailing," Pooler said.

Respondents gave the following as top reasons for choosing virtual colonoscopy screening (more than one response was allowed):

  • Noninvasiveness (68%)
  • Avoidance of sedation/anesthesia (63%)
  • Ability to drive after test (49%)
  • Avoidance of optical colonoscopy risks (47%)
  • Ability to detect abnormalities outside colon (43%)

A total of 441 patients underwent both CTC and optical colonoscopy:

  • 77% preferred CTC, compared with 13% who preferred optical colonoscopy.
  • 30% stated that they would not have undergone optical colonoscopy screening if CTC were unavailable.

The 30% reflects the number of patients who admitted to having some hesitation about undergoing optical colonoscopy, Pooler said.

"Our feeling is that this number may actually be an underestimation, in that it's quite easy to indicate on a survey that, yes, you would be willing to undergo a prep and an invasive optical colonoscopy, whereas the number of people who may actually follow through with that in reality could be lower," he said.

The low 13% preference rate for conventional colonoscopy is reflected in the reasons for choosing VC, he said.

"The findings tell us that our respondents had a very high level of satisfaction with virtual colonoscopy, and showed a preference for virtual colonoscopy over optical colonoscopy when given a choice," Pooler said. "Where we feel this may come into play is that obviously everybody would like to see more people getting screened for colorectal cancer."

The introduction of virtual colonoscopy in areas where optical colonoscopy is the only real option may lead to "an increase in the overall number of people who choose to get screened just because they have another option that seems to be preferable," Pooler said.

By now CTC is well-established, Kim said in the conclusion of his talk. "It's no longer considered experimental, and we have a large pool of people in our referral base," he said. "Performance variables are not questioned at this point, and referring physicians feel it is equivalent to optical colonoscopy."


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