Colonoscopy imperfect but suggested

Tue., Dec. 23, 2008

By Liz Szabo USA Today

Questions you need to ask

Douglas Rex, director of endoscopy at Indiana University Hospital, says patients should ask these questions when selecting a gastroenterologist to perform a colonoscopy:

•Are you familiar with flat lesions?

•How often do you find polyps? Studies show that properly done colonoscopies find precancerous polyps in about 25 percent of men and 15 percent of women.

•How much time do you spend when withdrawing the scope? Rex says doctors need to spend at least six minutes during this final phase.

•Can you document that you have examined the entire colon? Rex says it takes skill and patience to thread the scope to the very end of the colon, where tumors may be lurking. But he says patients can ask to see the doctor’s notes or even photos documenting the anatomy of the end of the colon.

Experts say a colonoscopy is still among the best ways to save lives from colorectal cancer, in spite of recent reports about the test’s limitations.

A study in last week’s Annals of Internal Medicine found that the exam’s benefits are decidedly lopsided. Although the tests reduced deaths from cancers found on the left side of the colon – the part that begins with the rectum – by 67 percent, colonoscopies didn’t reduce the risk of death from cancers that arise on the right side.

Other recent research has shown that colonoscopies can find many round polyps, but often miss flat or indented lesions.

Also last week, the Food and Drug Administration issued a “black box” warning about two of the pills used to cleanse the bowels before colonoscopies, which may increase the risk of kidney damage.

Douglas Rex, director of endoscopy at Indiana University Hospital, notes that complications are relatively rare. And while the exams aren’t perfect, they can prevent 50 percent to 70 percent of colorectal cancer deaths, he says.

The American Cancer Society hasn’t changed its recommendations about colorectal screenings, says the society’s Robert Smith. Liquid bowel preparations, available by prescription, are safe, although most patients hate drinking them.

Smith says noninvasive screenings, called annual fecal occult blood tests, which don’t require extensive bowel cleansing, are another option.

Patients who opt for a colonoscopy – which lets doctors detect and remove polyps in one procedure – should look for the most skilled gastroenterologist possible, Smith says. Doctors should have performed at least 200 colonoscopies, he says, and should perform them regularly to keep their skills current.

Patients also can take steps to make sure their colonoscopies are accurate.

They should ask about taking their bowel preps in two doses, Rex says; splitting the doses prevents mucus from coating and obscuring the beginning of the colon.

Patients also should take the second dose no later than five hours before their procedure to make sure that their colon stays as clean and empty as possible. Clear colons provide doctors with the best views of tissue, allowing them to spot hard-to-see polyps.