Gastroenterologists embrace VC screening, with caveats

BOSTON - Gastroenterology's visit this week to virtual colonoscopy's biggest meeting wasn't quite on par with Nixon's historic 1972 visit to China. After all, the two medical specialties have forged a committed -- if wary -- relationship in recent years.

By this time last fall, for example, the American Gastroenterological Association (AGA) of Bethesda, MD, had already endorsed the use of screening virtual colonoscopy (VC or CT colonography) (Gastroenterology, September 2007, Vol. 133:3, pp. 1005-1024).

Still, Monday's talk at the International Symposium on Virtual Colonoscopy by AGA Institute president Dr. Nicholas LaRusso seemed to underscore the significance of a growing collaboration between gastroenterologists and radiologists on the issue of VC screening. The universal benefits of the technology include, first and foremost, the potential for better screening compliance if patients are able to choose VC as an option. There also is the certainty of mutual patient referrals -- to radiologists when optical colonoscopy is incomplete, and to gastroenterologists when VC results are positive and the patient needs colonoscopy and polypectomy.

"They [the AGA] are our friends," said Dr. Elizabeth McFarland, a radiologist at St. Lukes Center for Diagnostic Imaging in Chesterfield, MO, and member of the U.S. Multisociety Task Force on Colorectal Cancer.

"The primary concern of the AGA continues to be patient care," said LaRusso, who is also a professor of medicine at the Mayo Clinic School of Medicine in Rochester, MN. "You're all familiar with the problem that we have, which is that colon cancer is essentially curable and preventable with adequate screening, and currently the number of people who are screened is inadequate."

Optical colonoscopy will remain the gold standard for colorectal cancer screening because it's the only test that both detects and removes polyps, LaRusso said. And unlike other cancers, the history of colorectal carcinoma is well understood, beginning with polyps and advancing to malignant transformation. In that context, "the AGA supports virtual colonoscopy and its potential to increase screening rates, if the patients and their physicians believe that this technique is appropriate for the individual patient," LaRusso said.

The organization's support is part of a broader coalition that includes the Atlanta-based American Cancer Society (ACS), the Reston, VA-based American College of Radiology (ACR), and the U.S. Multi-Society Task Force on Colorectal Cancer, which in March published a series of screening guidelines that include optical colonoscopy (every 10 years), flexible sigmoidoscopy (every five years), double contrast barium enema (every five years), annual guaiac fecal occult blood testing (gFOBT), annual fecal immunochemical test (FIT), and stool DNA testing (without a frequency recommendation) as the ACS guidelines for the early detection of colorectal cancer.

"The emphasis of those guidelines is that the primary goal of screening is cancer prevention and not simply cancer detection," LaRusso said. "I think this was a triumph for the organizations, that we could come together and work though a consensus process that will help physicians and patients understand what their options are for increased screening."

Despite its potential, CT colonography (CTC) has significant limitations, LaRusso said. "The hope is that through collaborative research efforts we might be able to answer questions regarding sensitivity and specificity for small and diminutive polyps, standardized reporting, training, and technology requirements," he said.

To that end, the societies continue to meet and discuss these issues, and the AGA will visit the ACR's new education center in Reston, VA, LaRusso said. Exposure to ionizing radiation through repeated VC screening, as well as optimal surveillance intervals, particularly when small polyps are detected, continue to be of concern to the AGA, he said, and research to date does not adequately address the issue.

Training task force

In support of gastroenterologists seeking VC training, last year the AGA Institute convened a task force of gastroenterologists and radiologists to develop the minimum training standards necessary for gastroenterologists to become proficient in the procedure, he said. The group concluded that after formal training that includes the successful interpretation of at least 75 cases, gastroenterologists should participate in a mentored VC preceptorship that includes closely monitored interpretation of 25 to 50 additional cases. The institute sponsored two didactic courses and two hands-on courses for gastroenterologists this year, with additional courses being planned for 2009.

"Currently, there are active discussions between [the ACR and the AGA Institute] regarding the benefits of joint task forces to review accreditation requirements, discuss quality initiatives, address reimbursement issues, and discuss research and education efforts, and we believe that a lot more can be accomplished by cooperation between our organizations," LaRusso said.

With regard to the complicated issue of reimbursement, the institute is pursuing VC reimbursement by the Centers for Medicare and Medicaid Services (CMS) through both the American Medical Association's current procedure terminology (CPT) codes and through a national coverage determination (NCD) process, he said.

As for the CPT codes, the AGA advocates a combined diagnostic and screening category 1 CPT code that can be used by any trained physician to perform VC. However, in a major point of contention with radiologists, gastroenterology seeks to decouple VC screening of the colon from the search for extracolonic findings. Decoupling would allow gastroenterologists to bill for colon screening while passing on the task of extracolonic evaluation, which presents a significant training hurdle for them as a group, to a radiologist who would be paid separately. Radiologists, who are trained to look for extracolonic findings, strongly oppose the split code due to liability and other issues.

"Ideally we'd like a single [CPT code] application to be submitted by GI and radiology because we think it will carry more weight," LaRusso said. Time is of the essence if the CPT code is to be ready by 2010. The deadline for submission is November 5, 2008, he said.

As for the NCD, the working group has responded to CMS' requests for public input. The CMS decision will be delayed until February 2009, and the final decision is expected in 2009, he said. As part of the decision-making process, CMS has scheduled a public meeting for November 19, at which time the GI/radiologist working group will make a recommendation as to whether CMS should cover VC screening, LaRusso said.

"Our fundamental position is that [the AGA Institute] supports coverage for screening CTC as long as CMS requires as a condition of coverage implementation and compliance with training and equipment standards, certification programs, and definition of appropriate episodes of care," he said.

Patients need to know if diminutive polyps are not being reported, so as to enable patients to make informed decisions regarding their care, LaRusso added. The AGA Institute strongly supports the ACR's data registry and believes that reporting to it should be mandatory, he said.

With regard to episodes of care, La Russo bought himself some controversy with his statement that "only truly asymptomatic patients should be screened with CTC." Radiologists believe any number of applications for CTC may be performed appropriately in symptomatic patients.

LaRusso also said that cross-specialty care models (such as same-day colonoscopy referral) should be in place to guarantee rapid follow-up care, including colonoscopy referral for all patients with a polyp 6 mm or larger, meaning that "30% to 51%" of patients testing positive at VC might ultimately be referred for colonoscopy -- a figure that radiologists in attendance dismissed as economically and practically unworkable as well as unnecessary.

"The AGA supports CTC in its potential to increase screening rates with the caveat that additional work is necessary with regard to quality, accreditation, reimbursement, reporting, training, technology, and standards," LaRusso concluded. "We think this can be accomplished most effectively through a partnership between the AGA and the ACR to ensure that CTC is done in a responsible way for this new and exciting technique," he said.

Radiologists take issue

At a panel discussion following Monday's presentations by LaRusso and others, radiologists said they welcomed their collaboration with the AGA Institute. Yet there was disagreement over some of LaRusso's statements, which radiologists said were not only impractical in some cases, but not always aligned with the AGA's own previously stated positions.

With regard to colonoscopy referral, it is clear that cross-specialty consensus is incomplete. The AGA's September 2007 Gastroenterology paper supporting CTC, for example, acknowledges that "full consensus relating to the reporting or management of subcentimeter polyps discovered at CT colonography has not been reached among all groups. It is generally agreed that the presence of three or more small polyps increases the risk of developing colorectal cancer." Does this mean every case of a polyp 6 mm and larger needs a colonoscopy?

Attendee Dr. Seth Glick, a clinical professor of radiology at the University of Pennsylvania in Philadelphia, questioned LaRusso's statement that every polyp needs to be reported, no matter how small. He said that the reporting of diminutive lesions cannot be accomplished with confidence at CTC, rendering the practice useless and perhaps even detrimental to patient care.

"What happens with the confidence of what is and isn't a polyp?" Glick said. "There are all these grays of interpretation. In that context if there is a discrepancy between that finding and CTC, how does that get resolved? It's going to be a fairly frequent occurrence and it's not going to be a trivial issue."

"The issue of interpretation, I think, cries out for additional research," LaRusso said. "The propensity for small polyps to undergo malignant transformation remains somewhat unclear, which is a factor that needs to be considered. So I think that the position is that further clarification of the importance of small polyps is required as well as evaluation of sensitivity and specificity.... I don't think we can ignore small polyps and I think we need further information on what the relevance of those are." More research and continually improving skills should be expected to clarify the reporting of diminutive polyps, he said.

Dr. Matthew Barish from Stony Brook University Medical Center in New York said it would be unhelpful to supply the referring physician with reports of "innumerable potential polyps. Colonoscopy referral rates would rise inappropriately, so there has to be some balance between referral rates and risk, and the idea that we may not know everything but we have to deal with it today," he said.

Pending additional research, one issue that remains to be addressed in cross-specialty discussions is the disposition of discordant findings between CTC and colonoscopy in practice, another attendee said. For its part, the American Medical Association has gone in the direction of having each specialty determine its own reporting standards.

A wealth of information is already available from several studies on the natural history of diminutive polyps, and more is on the way, said Dr. Perry Pickhardt from the University of Wisconsin in Madison. The verdict: most small lesions do not grow, and the rate of malignant transformation is extremely low, at less than 1%, he said.

In terms of colonoscopy referral rates, Dr. Abraham Dachman from the University of Chicago cited a study from the Madison group that included more than 3,100 patients reported last year, showing a more realistic colonoscopy referral rate of 7.9% for patients who underwent primary CTC screening (New England Journal of Medicine, October 4, 2007, Vol. 357:14, pp. 1403-1412).

As the final agreements are hammered out, radiologists want to ensure that healthcare budgets and patients are protected from the possibility of gastroenterologists self-referring their own CTC patients to follow-up colonoscopy, Dachman said. For their part, gastroenterologists are keen to avoid being excluded from reading CTC studies by the necessity of searching for extracolonic abnormalities.

"The position of the AGA is that an adequately trained gastroenterologist brings particular expertise to the examination of the colon and not to extracolonic manifestations," LaRusso said. "So I think our focus is on the coding for colonic abnormalities."

"My personal opinion is that gastroenterologists can have any patient they can talk into being scoped," quipped course director Dr. Matthew Barish over lunch. "VC should get everyone else."

Only time will tell how many of those VC providers will be gastroenterologists.

By Eric Barnes staff writer
October 28, 2008

Related Reading

CMS announces VC evidence meeting, September 26, 2008

ACR, others exhort CMS to cover virtual colonoscopy, June 19, 2008

CMS launches comment period for VC coverage, May 20, 2008

American Cancer Society recognizes virtual colonoscopy screening benefit, March 5, 2008

Bill introduced to add VC to Medicare screening coverage, December 20, 2007

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