WHAT TO TELL YOUR PATIENTS

Less invasive virtual colonoscopy imaging finds more polyps but...

...you still have to biopsy them and test facilities are rare

By Julia Cyboran

Who and when to test The colonoscopy is a test that patients never look forward to. That said, the colonoscopy is an essential screening tool for colorectal cancer. In 1998, Health Canada established a National Committee to look into the importance of colorectal cancer screening. The committee outlined specific guidelines: The fecal occult blood test is the recommended entry-test. Screening is to be made available to people 50-74 years of age. Individuals are to be screened at least every two years. If the fecal occult blood test is positive, further testing, including a colonoscopy, is indicated.

When she was 68 Phyllis Barek was diagnosed with colorectal cancer. She underwent emergency surgery and then chemotherapy. Her daughter Milena was 46 at the time and wanted to be sure she was colon cancer-free. Though the guidelines suggest testing begin at age 50, given the family history, her GP referred her to a gastro for a colonoscopy.

That was five years ago and she's had the procedure twice since then. She finds it inconvenient, invasive and uncomfortable.

Late last fall when she came in for her third test, she was armed with a newspaper article which described virtual colonoscopy. The article quoted a patient survey indicating there were fewer patient complaints using the new procedures 38% than with the standard test which 51% found uncomfortable.

Her question: Could she have a virtual colonoscopy?

STANDARD VERSUS VIRTUAL
The article in Milena's newspaper was based on a paper presented at the Annual Meeting of the Radiological Society of North America and reported in the December issue of the New England Journal of Medicine. The study suggested that in some cases a virtual colonoscopy picked up on even more polyps than the traditional method. Virtual colonoscopy uses a CT scanner to detect polyps in the colon by creating a 3D image of the colon walls. The 15-minute test simply requires patients to lie down and hold their breath for 10 seconds while the scan is being taken.

Dr Jean Maroun, Head of Medical Oncology at the Ottawa Regional Cancer Centre believes that the virtual colonoscopy is a viable solution, although it is still in the early stages of development. "At the moment the virtual colonoscopy is still experimental. There are a lot of studies trying to validate the process," he says. "I hope it will be proven to be accountable."

He also believes that the virtual colonoscopy could make colorectal cancer screening more accessible. "It is an easier way to screen, without having patients go through the actual colonoscopy. The virtual colonoscopy would allow doctors to screen people who don't need a colonoscopy but still need to be tested for colorectal cancer."

The virtual colonoscopy has been around for about 10 years but has not been on the recommended list of screening tests. The report on the efficacy of the virtual colonoscopy sparked debate in the medical community. In the US, the American Society for Gastrointestinal Endoscopy Technological Assessment Committee issued a statement recommending the standard colonoscopy over the virtual one. Their main point was that a virtual colonoscopy does not allow the physician to remove polyps or do a biopsy, which would require a second procedure.

HERE'S WHAT TO TELL YOUR PATIENTS ABOUT A VIRTUAL COLONOSCOPY:

• Virtual colonoscopy is not widely available in Canada.

• It still requires patients to take laxatives 24 hours prior to the exam.

• The patient is not sedated before the exam, even though a small rectal catheter is inserted for the CT scan.

• If polyps are detected, a regular colonoscopy is required to remove the polyps and to do a biopsy.