CHICAGO -- A new method offers more accurate and less invasive scans for potentially cancerous bowel growths for average-risk patients than are possible now by a conventional colonoscopy, according to a new study.

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Video: Virtual Colonoscopy More On Colonoscopy

But researchers say it still won't be something to look forward to.

Colon polyps are benign growths that may develop into colon cancer if not removed. Conventional colonoscopy requires doctors to use a flexible tube to snake a camera up the bowel, and patients need sedation.

But many people resist the screening because of the discomfort caused by colonoscopy and its preparation.

The computed tomography colonography, known as virtual colonoscopy, uses a scanner to get three-dimensional images of the bowel. Researchers say it had a higher success rate in spotting growths, and it does not require sedation. The procedure is also less costly than the conventional method and more convenient, taking 15 minutes or less, because patients need not recover from sedation.

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The study of more than 1,200 adults was conducted at the National Naval Medical Centers in Bethesda, Md., the Naval Medical Center in San Diego, and at Walter Reed Army Medical Center in Washington, D.C.

In the study, virtual colonoscopy detected 92.6 percent of polyps 8 millimeters and greater, while conventional colonoscopy detected 89.5 percent of such polyps.

"I believe virtual colonoscopy will eventually join conventional colonoscopy as a major component of colorectal cancer screening in the U.S.," said Dr. Perry Pickhardt, lead researcher and now an associate professor of radiology at University of Wisconsin in Madison.

Pickhardt presented the study's findings Monday at a meeting of the Radiological Society of North America. The study will appear in next week's issue of the New England Journal of Medicine.

But with either test, patients must take laxatives to clear the bowel before the exam. And if the virtual colonoscopy turns up a growth, the patient must get a conventional colonoscopy so doctors can cut out the growth with a wire loop through the tube.

Lt. Col. J. Richard Choi, another of the study's researchers, said the goal of screening with virtual colonoscopy is to increase the number of patients that would participate.

"Even though colorectal cancer is the second leading cause of cancer death and is almost always preventable, less than half of eligible patients undergo any form of screening," Choi said.

A recent commentary in the Journal of the American Medical Association advised that colon screening with any test is recommended for anyone over the age of 50.

Dr. Douglas Rex, the president of the American College of Gastroenterology, said that although the findings are encouraging, the overall cost-effectiveness of virtual colonoscopy are still uncertain, as are the risks of radiation.

Additional Resources:

• Radiological Society of North America
• American College of Gastroenterology
• American Cancer Society