Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Colorectal Cancer Health Center

Font Size

Will Colonoscopy Meet Its Match?


"Right now, the number of Americans being screened for colon cancer is less than 40% of the patients who should be screened, so there is a huge number of people out there who are just unscreened," Yee tells WebMD. "The hope is that using this noninvasive technique, with basically no risk, that we can increase the number of patients screened and we will find more lesions."

Screening isn't perfect, however. It just increases the odds of discovering the disease in its earliest stages when the chance of cure is greatest. Yee and colleagues cite studies showing that standard colonoscopy can still miss seeing a portion of the colon in up to 5% of cases, even when it is performed by an experienced gastroenterologist. In addition, the procedure may miss up to 20% of possibly cancerous growths.

"We consider standard colonoscopy to be the gold standard, but we have no idea how many polyps they miss," adds Amin Chaoui, MD, assistant professor of radiology at Boston University School of Medicine, in an interview with WebMD. "There have been a few studies where they had two people doing a colonoscopy back to back and found that they could miss up to 15% of polyps in the same patient, depending on how fast the colonoscopist goes." Chaoui was not involved in the UCSF study.

And although colonoscopy is generally safe when properly performed, in about 1 in 1,000 cases there is accidental perforation of the bowel wall, a potentially serious event.

Both techniques -- virtual and conventional -- also share some of the same downsides. Currently, both require the bowel to be cleansed through a regimen involving diet restrictions and high-power laxatives, a prospect that many patients find as unappetizing as the procedure itself. Some researchers are working on methods for "tagging" feces and fluids within the bowel so that the computer can then subtract them from the image, thereby getting a clean picture of the colon without the need for purging it of all contents.

But don't look for virtual colonoscopy yet in a doctor's office near you, cautions a gastroenterologist who has looked at the technique but was not involved in the current study.

Today on WebMD

Colorectal cancer cells
The right diagnosis is the most important factor.
man with a doctor
Our health check will steer you in the right direction.
sauteed cherry tomatoes
Fight cancer one plate at a time.
bladder cancer x-ray
Do you know the warning signs?
Colon vs Rectal Cancer
New Colorectal Treatments
can lack of sleep affect your immune system
Cancer Facts Quiz
Virtual Colonoscopy
Picture of the Colon
Vitamin D