• Health reform
• EMRs
• Medicare
• Liability
• AMA House
• » More

• Contract Language
• Ethics Forum
• In the Courts
• Practice Management
• Technically Speaking
• » More

• Issue dates
• Regions
• Health plans
• Sections
• News briefs
• Columns
• Editorials
• Letters
• Series
• Writers
• Other years

• Search tips
• Email alert
• RSS
• Mobile
• Subscribe
• Institutions
• Staff directory
• Advertising
• Permissions
• Reprints
• News media
• Site guide
• Useful links
• About
• Premium
• Contact

• AMA Wire
• CPT
• DMPHP
• JAMA
• JAMA&Archives
• news@JAMA
• Virtual Mentor
• Physician jobs

Colon cancer screening now can go noninvasive route

Virtual colonoscopies already are proving an effective cancer screening technique for some patients, but polyp removal still requires conventional means.

By Susan J. Landers, amednews staff. Sept. 15, 2003.

• PRINT|
• E-MAIL|
• RESPOND|
• REPRINTS|
• SHARE
•  

Washington -- No one considers a colonoscopy to be pleasant. Even physicians who recommend the screening procedure for others have been known to postpone it when they are the patients.

That's why it's hardly a surprise that a virtual version of the test is attracting attention.

Although conventional colonoscopies are the current gold standard for colon cancer screening, they aren't going to be effective if people avoid them.

"Less than half of the individuals who should be screened for colon cancer are screened appropriately," said Matthew Barish, MD, director of the 3D and Image Processing Center at Brigham and Women's Hospital in Boston. "A large number of people do not undergo screening because they look at it as uncomfortable or embarrassing."

As a result, many physicians are exploring virtual colonoscopies as a way to substantially boost the numbers of patients willing to undergo the life-saving procedure.

Virtual colonoscopy is an imaging technique of the large bowel or colon using CT or MRI scans. A full cleansing prep is required, but the procedure does not require sedation. The scans are being recommended for individuals at risk for colon cancer but for whom sedation, required of conventional colonoscopy, poses a risk. They also are recommended for those few whose bowels contain an obstruction that blocks passage of the tube used in conventional colonoscopies.

Most agree it is important to get people screened. After all, colon cancer is the second most common cause of cancer deaths in the nation. The disease often begins as malignant cells that form in slow-growing polyps attached to the inner surface of the bowel. Removing the polyps early is an effective means of prevention.

"Right now, whenever someone dies of colon cancer, it just breaks your heart because it is so preventable," said Blair Lewis, MD, a gastroenterologist and clinical professor of medicine at Mount Sinai School of Medicine in New York City.

Dr. Lewis welcomes the development of the virtual colonoscopy. "Any type of technology that comes along and is more acceptable to the people is a great thing."

Plus, data show that one in four people will have a polyp in their colon at some point in their lives. Therefore, gastroenterologists likely will have as much business as they can handle just removing polyps from the potentially larger number of people screened via virtual colonoscopy. Virtual surgery for removal of polyps is not an option.

"From a health care point of view and a business point of view, it's good -- good all the way around," Dr. Lewis said. Early research findings also have been encouraging. Studies have found that virtual colonoscopies performed by well-trained radiologists using CT scans and sophisticated new software compared favorably with conventional colonoscopies at detecting larger polyps.

While most are optimistic about the new technique, guidelines have yet to been rewritten to include virtual colonoscopies. The U.S. Preventive Services Task Force warns that lower accuracy may occur when CT scans are performed by less experienced examiners and that small and flat polyps are less well visualized on CT colography.

Additional studies are under way, and results should be available within the next few years that could help determine the future of the high-tech procedure. A multicenter study is now enrolling 2,000 participants in a trial that will compare results of conventional colonoscopy, virtual colonoscopy and barium enemas.

Until the data line up more firmly on the virtual side, the National Cancer Institute and the American Cancer Society are being cautious. "We consider virtual colonoscopy to still be a research tool," said Ernest Hawk, MD, MPH, NCI chief of gastrointestinal cancer prevention. "It remains in our view a promising avenue to follow."

"We view it as a promising but as yet unproven technology," agreed Durado Brooks, MD, MPH, the American Cancer Society's director of colorectal cancer. Studies done so far have been on people at high risk for colon cancer, and the society is awaiting the results of studies on those at average risk for colon cancer.

Meanwhile, it appears that many people aren't waiting for definitive findings. They already are lining up. At least that's the case in Richmond, Va., where recent publicity yielded hundreds of calls for information and to schedule appointments, reported Mary Ann Turner, MD, professor of radiology and director of gastrointestinal radiology at Virginia Commonwealth University Medical Center. VCU does about five or six virtual colonoscopies a week and has a lengthy backlog of people interested in the procedure.

But there are still several important considerations to its use. Like its conventional counterpart, the virtual version requires a clean colon for the radiologist to get a good view.

Often the preparation for a colonoscopy -- liquid diet and laxatives -- is thought to be worse than the procedure itself. Plus, if polyps are found via the virtual colonoscopy, preparation would have to begin all over again for a conventional colonoscopy.

Virtual colonoscopies are not usually covered by health insurance, although case-by-case appeals can be made for coverage. Their cost ranges from about $600 to $1,000.

The virtual version also involves inserting a tube, though a much smaller one, into the rectum. This tube dispenses air to inflate the colon rather than snake its way along the entire colon as would be the case with a conventional colonoscopy.

Back to top

 ADDITIONAL INFORMATION: