Is there a role for the laxative free virtual colonoscopy?

Research radiologists at the Massachusetts General Hospital in Boston evaluated the accuracy and detail of imaging the colon (a virtual colonoscopy or colonography) with no laxatives as preparation and comparing it with traditional colonoscopy.  There are clear evidence based guidelines suggesting that all low-risk men and women have a screening for colon cancer with a colonoscopy at age 50.  If that study is normal they are directed to repeat it every 10 years.  Routine screening colonoscopies are discontinued after age 80 years old.  There is no question that screening colonoscopies save lives from colon cancer.  There is no question that the laxative taken the day before to clean you out, plus the actual procedure, are reasons that individuals avoid going for colon cancer screening.

The study directors fed their patients a low fiber diet before the scan. The patients drank an oral contrast material that marked stool feces and allowed the radiologists to distinguish colon abnormalities from retained feces and stool.  This virtual colonography was excellent at detecting larger colon adenomas of 10 mm or larger picking up 91% of the existing lesions as compared to 95% with traditional preparation and colonoscopy. The difference between the 91% on virtual colonography and 95% on traditional prep and colonoscopy was not felt to be statistically significant.   The virtual colonography didn’t do as well at detecting the smaller growths.  Researchers pointed out that “the vast majority of polyps that impact cancer and survival outcomes are 10 mm or larger.”  They went on to say that the “the laxative free method would likely be worthwhile as a way to reach the many adults whose strong aversion to laxative bowel preparations stops them from getting screened.”

Clearly getting screened is always preferable to no screening.   The laxative free virtual colonoscopy was not as good as the traditional colonoscopy at finding smaller lesions.

The data in this research study were based on the skill and experience of three radiologists only. Previous studies have emphasized the need to have an experienced radiologist interpret these studies.  The researchers did not discuss the radiation exposure, which is significant, with the virtual colonoscopy.   They additionally did not mention the cost which many health insurance companies will not pay for at this time.

Despite these issues it is wonderful to have another tool in the fight against colon cancer especially to offer to those patients who have said they will “never” have a colonoscopy.

Steven Reznick is an internal medicine physician and can be reached at Boca Raton Concierge Doctor.

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  • Kristy Sokoloski

    A very interesting article. Another reason that people many times don’t get colonoscopy is because of the cost to have it done. Even though someone may have insurance to pay the majority of the cost, the part the patient pays for co-insurance and deductible (if not met yet) are also very cost prohibitive. As a result of this patients are not able to get this vital screening or other tests that may be needed to further determine what type of treatment is necessary depending on the results of the colonoscopy. The same also applies to treatment that may be necessary.


    “Despite these issues it is wonderful to have another tool in the fight against colon cancer especially to offer to those patients who have said they will “never” have a colonoscopy.”

    There are several. Several studies, including this study from the NEJM have found that the non-invasive, relatively inexpensive option of yearly FIT testing (fecal immunotesting) results in greater screening rates and similar colon cancer detection rates to colonoscopy. It also eliminates the discomfort and risk involved in anesthesia and endoscopy, which is of significant concern for low-risk individuals undergoing routine screening.

    • Donna McMurtry

      What’s a lay person to think? So much controversy over whether or not ROUTINE colonoscopy screening is really necessary. My research shows medical opinions all over the map! My doc says no. I got a second opinion. They too said no- not unless family history or symptoms indicating a problem. I was told that the FIT test was the way to go ( I am 65). I am not afraid of a colonoscopy- but, am not eager to undergo one if it really is not necessary. Every Tom Dick and Harry I know has had a colonoscopy as part of routine screening. Doc says its almost like a “fad” in the non medical community just like everyone running for B12 shots- I dont know- my gut says what the heck- it can’t hurt, but my doc says there are risks, albeit rare. So I guess we lay folks will just have to go with our “gut”:) so to speak…. If only someone in authority would make a decision that we could all live by instead of one that we could die from by either having it done or not having it done! Beats me!

      • southerndoc1

        Great post.
        This is where the proponents of evidence-based medicine performed by pay-for-performance automatons suddenly go quiet: there are surprisingly few black and white situations in medicine where every patient can be treated identically.

  • JeanArt

    I really do wish the experts would quit recommending colonoscopy as the only (or best) screening tool for those 50 and over and at average risk. Colonoscopy is expensive and invasive with a small potential for complications. And obviously another reason some may not want one is because of the embarrassment factor, which medical practitioners never seem to recognize (or pretend not to), nor do they do things to address it (like provide some kind of disposable short, same gender team, etc.). I personally would much rather go the yearly FIT route. It would seem a lot more practical and inexpensive and would only send those on to colonoscopy who truly need it. I think the media, medical establishment, etc. should start getting the word out that colonoscopy is not the ONLY screening method and give FIT equal billing time.

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