Dr. Patricia Yarberry Allen is a collaborative physician. This week, during Colorectal Cancer Awareness Month, she asks gastroenterologist Brian Landzberg to advise a patient inquiring about that notorious day-before-the-colonoscopy bowel prep.


Dear Dr. Pat:

“I am 57 years old and have not yet had a successful colonoscopy. I tried three years ago to do the dreadful preparation before the colonoscopy, but was told by the specialist that the procedure could not be performed because my colon was “not cleaned out.” I did everything that I was told to do, but it didn’t work. I certainly don’t want to see those nurses and that doctor again, because I am still embarrassed. I investigated doing a virtual colonoscopy, but my GP told me that my colon would still need to be cleaned out or that wouldn’t work either.

I have had sluggish bowel function for my entire life. I was given castor oil by my grandmother when I was a child. Is there a special way for people like me who have severe constipation to clean their colon out? I really need this test now, because my brother was just diagnosed with stage 3 colon cancer. He had constipation too and never had the test until he had real symptoms. Now he is seriously ill. He has begged me to get this done.



Dr. Pat Responds:

Dear Constance:

Everyone dreads the colon cleanout procedure. It is worse than the colonoscopy, because sedation is given for that procedure! I have asked Dr. Brian Landzberg, Assistant Attending Physician at New York-Presbyterian Hospital, to answer your question. Dr. Landzberg is the gastroenterology specialist on the Women’s Voices for Change Medical Advisory Board.

Dr. Pat



Dr. Landzberg Responds:

Dear Constance:

Thank you for your question. It is particularly timely and appropriate for March, Colorectal Cancer Awareness Month!

Why is a screening colonoscopy important? Because during this procedure we can remove precancerous lesions, known as polyps (Figure A), and thus, in the vast majority of cases, prevent incurable colon cancer from ever occurring (Figure B).  If you ask patients who have been through a colonoscopy, the vast majority will tell you that the preparation is the worst part of the experience. The procedure itself should be a comfortable and, believe it or not, pleasant experience, with the benefit of the excellent sedation medications available to us. You are precisely correct that the option of CT colonography, a.k.a. virtual colonoscopy, requires at least as thorough a bowel preparation. And if polyps were found, you would then have to take a second preparation and have a traditional colonoscopy to remove them.

Screenshot_3_21_13_8_26_AMFigure A: Colonoscopy photographs of a polyp removed with a cautery snare. © Brian R. Landzberg, M.D.

Colonoscopy of colon cancerFigure B: Colonoscopy photograph of colon cancer.  © Brian R. Landzberg, M.D.

The quality of the preparation is important: A poorly prepared colon is one in which polyps and small cancers can be missed. As difficult as it is for a gastroenterologist to tell a patient that his or her procedure could not be effectively completed, it is the right call to make if there is inadequate visualization. Too often I hear about procedures that were completed with poor visualization, when it was not made clear to the patient that the test was non-diagnostic, and important lesions could have been missed.

The question of what is the best preparation method is difficult to answer. There really is no “one size fits all” prep. For some, a given regimen will be excessive, while for others it will be inadequate.  For patients with a history of sluggish colon or who have the benefit of knowing they had an incomplete bowel preparation, I would recommend a two-day preparation. You should be on a clear liquid diet for two days before the procedure. I generally have such a patient take Dulcolax and a bottle of magnesium citrate two days before the procedure and then a combination of Dulcolax and a mixture of Miralax and Gatorade one day prior to the procedure. There are occasions when I have prescribed an even more vigorous prep than this.

Being able to customize a bowel preparation for a patient (based on his or her bowel habits, medications, tolerance of large volumes of liquid, and colonoscopic history) is a reason why I like to meet patients in the office to take a proper history and discuss the procedure before the colonoscopy day. I am aware that this is omitted in the majority of gastroenterology practices.

Get the colonoscopy done.  Certainly don’t be embarrassed. Spread the word of your brother’s painful lesson about colon cancer and you can help save lives!

FIGURE C: Myths About Colon Cancer Screening

Myth #1  Colon cancer mainly affects men.  WRONG!

Fact: Roughly equal numbers of men and women are diagnosed with colon cancer.

Myth # 2  Only people with a family history should worry about it. WRONG!

Fact: Almost 75 percent of colon cancer cases do not have a family history of colon cancer.

Myth #3  I don’t have symptoms so I don’t need to be screened. WRONG!

Fact: In early stages, colon cancer generally gives no symptoms or warning. When symptoms and signs such as bleeding, constipation and anemia develop, it is often too late to cure.  

Myth #4  Colonoscopies are uncomfortable and time consuming. WRONG!

Fact: The procedure takes 15-30 minutes, sedation makes this a painless test and you can resume normal activities the next day.

Myth #5   Colon cancer can’t be prevented or cured and it’s always deadly , so don’t bother looking for it.  WRONG!

Long-term follow up data from the National Polyp Study confirm that colorectal cancer death can be dramatically reduced by colonoscopy and polyp removal.   If colon cancer is caught at early stage, the five year survival is 90%

Myth #6 :  Age is irrelevant to getting colon cancer. WRONG!

Over 90% of colon cancer occurs in people over the age of 50, which is why that is the age we start general screening.   Some patients may need to start screening or surveillance  at a younger age if risk factors such as family history of colon cancer or inflammatory bowel disease are present



Brian R. Landzberg, M.D., A.G.A.F., is Clinical Assistant Professor of Medicine in the Division of Gastroenterology and Hepatology at the Center for Advanced Digestive Care, Weill Medical College of Cornell University, and Assistant Attending Physician, New York-Presbyterian Hospital. His particular areas of clinical interest are celiac disease, functional gastrointestinal disorders including constipation, diarrhea and irritable bowel syndrome, inflammatory bowel disease, gastritis, GERD and liver disease. He has published and lectured on these topics and maintains a very active clinical practice on the Upper East Side of Manhattan.