You’re full of shit, and you’re going to have to deal with that

Having a colonoscopy? Those bowel cleanses remain a necessary inconvenience, but doctors are working to make them less unpleasant

April 19, 2017
There are viable alternatives to drinking a gallon of polyethylene glycol to prepare for a colonoscopy, but refusing to cleanse your bowels isn’t one of them. [Image credit: Wikimedia Commons user WhoIsJohnGalt | CC BY-SA 3.0]

Cleaning out your bowels is just as much fun as, well, cleaning out your bowels. But an arduous cleansing regimen is a necessary prerequisite to colon cancer screenings. The standard course of action is to chug about a gallon of a clear, bad-tasting laxative called polyethylene glycol, or PEG, and sit on the toilet until you run out of PEG or your gastrointestinal tract is all squeaky clean. It’s a crappy prescription — so much so that almost 40 percent of those who decide not to go through with a recommended colonoscopy say that they did so to avoid the preparation.

Bowel cleanses create a barrier for patients at risk of developing colorectal cancer, yet the procedure can cut the amount of deaths from colorectal cancer in half. Therefore, people started to wonder if such aggressive cleanses were really necessary.

Yes, they are. That’s what the studies — those that aren’t full of shit — say.

A poorly-prepared bowel can obscure polyps, the small growths of cells that grow on the colon and may develop into cancer, found a 2014 study published in the Journal of Gastrointestinal and Liver Diseases. While there’s no guarantee that catching colon cancer early will save a patient’s life, unnoticed polyps could make things worse.

Because colorectal cancer is the second-most common cause of deaths due to cancer in America — the Centers for Disease Control and Prevention reports that almost half of the roughly 136,000 Americans diagnosed with colorectal cancer in 2013 died from the disease — men and women who are at least fifty years old are encouraged to get a colonoscopy every ten years. If those people show symptoms, complications, or other warning signs, that rate increases.

So, while skimping out on prescribed cleanses may help with the most unpleasant part of a colonoscopy — a procedure that involves a physician sliding a small probe up the patient’s butt — it will compromise the cancer screening. Moreover, the authors of the study noted that patients who expected to have a bad time with their colonoscopy preparation didn’t cleanse as well as others, meaning these patients may have had colon polyps that were obscured by leftover residue.

“When you’re doing a colonoscopy, you want to get absolutely everything. You can’t have any significant residual stool, because you cannot miss anything,” said Dr. Corey Siegel, a gastroenterologist at Dartmouth College’s Geisel School of Medicine and cofounder of ColonaryConcepts, a company that seeks to improve the patient experience by providing alternatives to the standard PEG treatment.


Skipping a cleanse means you’ll have to do it again even sooner


Patients who went in for a colonoscopy without properly and completely cleansing their bowels were brought in for a repeat procedure much sooner, sometimes within a year.

A different 2014 study published in the Scandinavian Journal of Gastroenterology looked at over 10,000 colonoscopies and concluded that patients should be brought back for another colonoscopy after just three years if they failed to completely cleanse their bowels the first time around. The patients weren’t brought back for any sort of ironic punishment, but because polyps that were potentially obscured during the first screening may have developed into cancers and the doctors behind the study recommend getting a clearer picture. With colorectal cancer, early detection and treatment can be key.

“Bowel preparation is a key issue and quality indicator for colonoscopy,” said Dr. Theodor Voiosu, a practicing gastroenterologist at Colentina Clinical Hospital in Bucharest, Romania. He conducts research with the goal of improving the quality and comfort of bowel cleanses. “[Bowel preparation] affects all aspects of colonoscopy — the ease and comfort of the examination both from a patient and physician perspective, how effective it is in detecting lesions, how safely therapy can be conducted.”

Research shows that the best approach — the approach that actually requires drinking less PEG in the long run — is reflected in the colonoscopy prep tips assembled by the Colon Cancer Alliance: suck it up and let it all out.


PEG is no fun — so doctors are working on alternatives


But patient resistance to treatment cannot be discounted — fear of the procedure is a very real factor. Plus, colonoscopies can be expensive, with an average cost of about $2,000 for the uninsured. Colonoscopies are useless if people refuse to get them. Many researchers are investigating ways to improve the cleansing process. “We felt that a place where we really make things difficult for our patients is with colonoscopy preps,” said Siegel on his motivation to develop an alternative to the standard PEG treatment.

Researchers have found many different potential alternatives to a typical PEG dosage, including different ways to take the same drug, different drugs, and different ways to screen. The laxatives can be administered via food or a less-unpleasant drink, and other drugs have been tested as substitutes for PEG. But when it comes to accuracy, PEG is still the cleansing method preferred by these researchers. But other options that are less unpleasant to the patient but still adequately clean the bowel, such as reduced-dosage cleanses, are more preferred overall.

“The current paradigm is that bowel preparation is a trade-off between efficacy and comfort — more aggressive preps being less tolerated,” says Voiosu, who explained that even patients who follow a more aggressive cleansing method to the letter may be less likely to do so a second time.

Aside from comfort, there is also the matter of providing a cleansing treatment that’s best for a given person. One of Voiosu’s studies found that PEG was superior to an alternative cleansing drug, sodium picosulphate, but only if the patient followed the instructions.

Ongoing research conducted by Voiosu suggests that patients who are younger, more motivated, and better educated — especially regarding health literacy — are more likely to correctly follow the instructions for a proper PEG cleanse, whereas other cleanses would be more effective for others.

“We need to get rid of the ‘one-size-fits-all’ attitude in bowel prep,” Voiosu said. “As a physician, I am always in need of the best possible cleansing to ensure correct and safe examination but… I need to think about what their current experience means in terms of future compliance.”

Voiosu stressed the importance of caregivers providing clear instructions — he suggested that visual aids and phone reminders would be useful supplements.

“Previously, the whole procedure was very scary and confusing, with pharmacies telling you different things from the doctors or the internet,” said Siegel.

ColonaryConcepts, the company started by Siegel, is taking a new approach. He and his team recently completed a clinical trial to test whether their cleansing products are safe. Their products provide the usual PEG but in the form of food rather than a powder mixed with water. His goal was to allow patients to have a more varied diet while preparing for a colonoscopy in hopes that more people would follow through with the procedure.


No matter how you do it, you still need to cleanse


All of these new approaches, however, still emphasize the necessity of a spotless bowel. The misconception that perhaps cleanses are unnecessary or too extreme may stem from the availability of alternatives to colonoscopies. One of these alternatives is an annual fecal immunochemical test that scans stool for signs of cancer. While much less unpleasant for the patient, these tests are not quite as good at detecting cancer as colonoscopies. These tests aren’t designed to replace colonoscopies. Rather, a positive fecal test is a sign that a patient should have a colonoscopy, so they can be a useful first step before jumping into an invasive procedure.

Another alternative to the standard colonoscopy is a noninvasive, so-called virtual colonoscopy that relies on body scans rather than a physical probe. Researchers have published standards for colonoscopy preparations that require physicians to be able to detect polyps as small as five millimeters while conducting scans. However, research shows that the largest polyp found in about 40 percent of patients was smaller than the five-millimeter threshold, and the measurements of the scanners used to conduct these noninvasive surveillance colonoscopies can be off by several millimeters anyway.

“They seem to think that as long as we can get down to five millimeters, we won’t miss anything,” said Siegel, criticizing the standards that allow partial-cleanses.

For these so-called virtual colonoscopies to work, cleansing is just as necessary as for a conventional procedure. And when cancer is detected via virtual colonoscopy or a fecal immunochemical test, the next step is to verify the findings with a standard colonoscopy. So for those who need to undergo a colonoscopy, virtual or otherwise, a complete preparation is unavoidable.

“The number one important thing is, in whatever form the preparation may take … is to allow for optimal visibility of the colon,” said Siegel.

So, if you’re due for a colonoscopy, it may be tempting to take the easier way out and half-ass a cleanse that really requires a full-ass commitment. “There is no perfect preparation regimen likely to be available in the near future,” said Voiosu, “but there is still a lot of room for improvement by using the drugs we currently have in a more efficient, targeted manner.” If there’s any comfort to be had, take assurance in the fact that scientists are working hard to make the whole ordeal as quick and painless as they can.

About the Author

Dan Robitzski

Dan Robitzski graduated from Lafayette College with a B.S. in neuroscience and a minor in creative writing. Passionate about accessible information, Dan hopes to use science journalism as a way to bridge the communication gap among researchers, medical professionals, and the public. In his spare time, you can find him competing and coaching at fencing tournaments, pretending to understand pop culture references, and looking at cute rodents on the internet.

You can follow Dan on Twitter here.


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