Prepping for a Colonoscopy: Why It's a Necessary Evil
Though new techniques are on the horizon, doctors say colon-cleansing is here to stay
Thursday, May 30, 2013
Most people who've had a colonoscopy say the test itself is no big deal. It doesn't take a lot of time, and you're sedated.
What people really don't like, however, is the colon-cleansing preparation that's required before the test. People who've had a colonoscopy often say that the prep is the worst part of the whole procedure.
However, it's a crucial part of the procedure. If the bowel isn't thoroughly cleaned out, doctors might miss a pre-cancerous polyp during the colonoscopy because they simply can't see it.
"I've had patients tell me the prep was cruel and unusual punishment, but it clears the colon wall so we can identify polyps," said Dr. Grant Hutchins, a gastroenterologist at the Nebraska Medical Center in Omaha.
Dr. Pankaj Vashi, the national clinical director of gastroenterology and nutrition at the Cancer Treatment Centers of America in Chicago, agreed. "We're looking for very small lesions, from 3 millimeters to 1 centimeter," he said. "If the colon isn't completely cleaned out, we can potentially miss small polyps. It's a crucial thing to have a cleaned-out colon."
A 2012 study from the journal Gastrointestinal Endoscopy found that as many as a third of polyps are missed when people fail to adequately prepare for their colonoscopy.
So, why are some people short-changing their bowel preparation?
Some find that the necessary volume of liquid is difficult to drink, and some people balk at the taste of some of the preparation solutions, according to Hutchins.
In the past, colonoscopy preparation required drinking an entire gallon of a salty solution the night before the procedure. Today, most preparations require half that volume, Vashi said. Hutchins noted that minor flavoring has been added to some preparation solutions to make them more palatable.
Pills are now an option, though they must be consumed with liquids, and the standard prep relies on taking 32 pills, according to Vashi. Researchers are working on developing options with fewer tablets. Another option is to take the over-the-counter laxative MiraLAX, along with 64 ounces of a sports drink, such as Gatorade. It's also possible to split the preparation, doing half the night before and half in the morning, five hours or so before the colonoscopy.
Most doctors have a method that they prefer and will recommend. But if you've tried a particular method in the past and know you don't like it, ask your doctor what other options are available.
Whatever method of preparation is used, the goal is to induce diarrhea to clean out your bowels. So, plan to spend a lot of time in the bathroom. And to make the process as comfortable as possible, it's a good idea to buy flushable moist wipes.
Preparation also requires that you fast the day before the procedure, consuming only a clear liquid diet that doesn't contain any red or purple coloring, according to Hutchins. Examples of liquids that are OK to consume are water, apple juice, ginger ale, jello and clear broth.
People hoping to avoid the preparation by having a virtual colonoscopy -- a test that uses CT scanning technology to capture images of the bowel -- are out of luck. The virtual colonoscopy still requires bowel preparation, though researchers at the Mayo Clinic have come up with a new technique that requires just four cleansing tablets before a virtual colonoscopy. Also, Harvard researchers have developed a preparation that involves putting a contrast medium into low-fiber foods and snacks for two days before the test. The contrast agent makes fecal matter stand out on the scan, making it easy to remove from the image.
The drawback to virtual colonoscopy, however, is that if a polyp is found, you'll still need to undergo a regular colonoscopy.
Some researchers are hoping to develop screening tests that can bypass the colonoscopy altogether. A company called Exact Sciences has indicated that it intends to seek U.S. Food and Drug Administration approval for a noninvasive, DNA-based stool test it has developed. It's designed to detect changes in DNA that indicate cancerous or pre-cancerous changes. Of course, if cancerous changes were detected, you'd still need to have a colonoscopy.
Both Hutchins and Vashi said that cleaning out the bowel before colonoscopy will probably be a necessary part of the procedure for some time to come.
"We've come a long way already, and while we do keep on trying to make it easier for patients, we don't want to compromise the quality of the bowel preparation and the colonoscopy," Vashi said.