‘Virtual’ colonoscopy preferred by patients

By surveying patients who were screened for colorectal cancer, investigators at the Alvin J. Siteman Cancer Center at the School of Medicine and Barnes-Jewish Hospital found that most prefer “virtual” colonoscopy to traditional screening, but most had positive appraisals of both.

Patients didn’t, however, like the bowel preparation prior to either screening test.

Colonoscopy researchers
Investigators Stephen L. Ristvedt, Ph.D., assistangt professor of medical psychology in psychiatry, and Elizabeth G. McFaland, M.D., associate professor of radiology, review patient-response forms. — Photo by Bob Boston

The researchers reported their findings in the March issue of the American Journal of Gastroenterology.

“Colorectal cancers are very preventable and treatable,” said Stephen L. Ristvedt, Ph.D., assistant professor of medical psychology in psychiatry and lead author of the study. “But many people don’t get screened, and we want to understand what the barriers are.”

Although about 90 percent of colorectal cancers and deaths are thought to be preventable, colorectal cancer is the second-leading cause of cancer-related deaths in the United States among both men and women. It is more deadly than either prostate cancer or breast cancer and ranks only behind lung cancer in mortality.

Screening tests can identify the disease in its earliest stages when small growths called polyps can be found and removed before they become cancerous. Because there often are no symptoms associated with precancerous polyps, regular screening is key to reducing mortality.

“Colorectal cancer remains a leading cause ofcancer-related deaths because patients are reluctantto be screened,” said co-investigator Elizabeth G. McFarland, M.D., associate professor of radiology.

During standard colonoscopy, a tiny video camera is inserted into the colon through the rectum, and physicians can both visualize and remove any growths. Patients are sedated because of the invasive nature of the test.

During virtual colonoscopy, on the other hand, patients remain awake and alert and are asked to hold their breath for 10-20 seconds while computed tomography (CT) images of the colon are taken.

Although the test does not require the insertion of a camera, it does require that air be pump-ed into the rectum to inflate the colon. Some patients reported that this experience was unpleasant.

Because CT colonography is less invasive than traditional procedures and requires no sedation, McFarland has been leading an effort to compare its accuracy with standard colonoscopy, the current “gold standard” in colorectal screening.

If it proves to be as accurate at detecting polyps, its less-invasive nature might encourage more people to get screened.

The study included 120 patients who underwent a CT colonography followed by a traditional colonoscopy on the same day. Patients completed surveys about the screening tests at three different times: just prior to the CT colonography, between the CT test and the colonoscopy and again two to three days after the procedures.

“We asked what they expected in terms of pain, embarrassment and difficulty,” Ristvedt said. “Before the procedures, patients expected more pain with colonoscopy than with CT, but afterward many reported there actually was less pain and embarrassment for colonoscopy because they had been sedated and given pain medications during that procedure.”

The team did find, however, that almost 58 percent of patients said they would prefer CT colonography in the future. Seventeen percent said they would rather have a colonoscopy; 34 percent had no preference.

Patients reported little pain, difficulty or embarrassment for either procedure, and most people agreed that the advance bowel preparation required for both procedures was unpleasant.

“Of all of the issues surrounding these tests, bowel preparation seems to be the greatest barrier to compliance for colorectal screening,” McFarland said. “That’s because patients can’t eat what they normally eat, and they have to drink a large volume of a liquid that helps to cleanse their colon.”

Some patients said the liquid nauseates them. Others actually lose electrolytes and become weak from the cleansing process. Presently, however, the preparation is essential for both tests.

“There are certain techniques in development that may change that in the future,” McFarland said. “But for now, we have to be concerned that colorectal cancer is a leading cause of cancerrelated death because of non-compliance with screening.

That’s what makes it so tragic because if you detect the disease early, you can prevent it. And right now, regardless of the cause, the fact is that many patients are reluctant to get screened.”