Health

Virtual Colonoscopies

By CBSNews.com staff CBSNews.com staff

January 31, 2002 / 8:40 AM EST / CBS

Colon cancer kills 57,000 Americans every year but having your colon examined can be an unpleasant experience, to say the least.

A traditional colonoscopy is considered the gold standard because it is extremely thorough. It requires inserting six feet of tubing into the rectum. A doctor uses a small lens to look at the entire length of the colon. The procedure can take up to an hour. The anesthesia can make some patients nauseous, putting them out of commission for the entire day. A recent study showed the current screening method for colon cancer, sigmoidoscopy, has limited effectiveness. It can actually miss cancer a third of the time.

But News 2's Paul Moniz reports there's a new type of colonoscopy that's virtually pain free. The virtual colonoscopy is a high tech procedure using a CAT scan to inspect the colon, producing images out of a science fiction movie.

A two-inch catheter, the diameter of a pencil, is inserted into the rectum instead of six feet of tubing. A small amount of air is pumped into the colon before the patient holds his breath for 30 seconds.

The procedure is over after 10 minutes without anesthesia, invasive tubes and with only mild discomfort from the excess gas.

New York University Medical Center is just one institution that is studying the virtual colonoscopy.

Mark Macari, a radiologist conducting the study, says it's a win-win for patients.

"The study takes five or 10 minutes," he says. "The patients can go back to work, play golf or tennis, whatever they want to do."

While initial studies show the virtual and traditional procedures are effective at finding larger polyps, virtual testing may miss the smallest ones.

One study showed a 21 percent false positive rate with virtual colonoscopies and if there is a polyp, it cannot remove it like a traditional colonoscopy can.

"I think it is just too early to know how colonoscopy and virtual colonoscopy compare," says Dr. Mark Pochapin, a gastroenterologist at New York's Weill Cornell Medical Center who performs the traditional procedure.

But he still sees some benefit to the virtual procedure.

"I think that there are plenty of individuals who are so frightened of having the procedure like a colonoscopy done that given a choice, rather than having no screening at all, they may opt to have virtual colonoscopy," he says.

The $650 virtual colonoscopy is not covered by insurance but traditional colonoscopies generally are.

Doctors recommend beginning screening for colon cancer at age 50.

If there is a family history of colon cancer, testing should start by age 40.

Tests should be repeated every five to 10 years.

The American Cancer Society has not changed its recommendations about sigmoidoscopies, despite reports of their limited effectiveness, which means if you get any type of colonoscopy for screening purposes, you may have to absorb the cost yourself.

A doctor's referral is required to participate in the virtual colonoscpy study. Contact Linda Michaels at (212)263-8904.