Preparing for Colonoscopy
What is colonoscopy?
Colonoscopy is a procedure which enables a physician (usually a gastroenterologist) to directly image and examine the entire colon. It is effective in the diagnosis and/or evaluation of various GI disorders (e.g. colon polyps, colon cancer, diverticulosis, inflammatory bowel disease, bleeding, change in bowel habits, abdominal pain, obstruction and abnormal x-rays or CT scans) as well as in providing therapy (for example, removal of polyps or control of bleeding). It is also used for screening for colon cancer. A key advantage of this technique is that it allows both imaging of abnormal findings and also therapy or removal of these lesions during the same examination. This procedure is particularly helpful for identification and removal of precancerous polyps.
What is my risk of developing colon cancer if I live in the United States?
Your lifetime risk (defined as life to 85 years old) is approximately 6% (male or female). Your risk is roughly doubled if one (1) first degree relative (parent, sibling or child) had colon cancer or polyps after age 50, and is higher if the cancer or polyps were diagnosed at a younger age or if more members of your family are affected. Certain inherited disorders, for example, polyposis syndromes and hereditary non-polyposis colorectal cancer, can increase your risk of developing colon cancer, but those are rare. Other important risk factors include obesity, cigarette smoking, inflammatory conditions in the colon such as Crohn’s, Colitis and Ulcerative Colitis, red meat consumption, and excessive alcohol consumption. Your doctor is in the best position to discuss whether your personal or family history suggests one of those conditions.
When should I have a colonoscopy?
If you have no colorectal symptoms, family history of colon cancer, polyps or inflammatory bowel disease you should have your first exam at age 45 whether you are a man or a woman.
If one or more first degree relative (parent, sibling or child) has had a precancerous polyp or colon cancer, the general guideline is to begin colon cancer screening 10 years younger than the youngest age of the family member with colon cancer, or age 40, whichever is younger. There are additional guidelines for suspected or confirmed rare syndromes, and you should discuss these options with your doctor.
What is the prep like for a colonoscopy and how many different preps are there?
This is an important obstacle in the eyes of many patients to getting a colonoscopy, but it need not be! There are a variety of preparation methods for colonoscopy ranging from liquids (of varying quantity) with or without enemas, to pills, which rid your colon of feces. A clean colon is essential to allow for a careful examination for polyps or other abnormalities. Your doctor can discuss and prescribe the most appropriate preparation method for you, taking into account various factors such as your age, personal preferences, kidney function and physical stamina.
The most popular preparation used for colonoscopy involves drinking a volume of solution of polyethylene glycol (PEG). This solution causes a diarrhea that effectively rids the colon of its contents. Various fruit flavors are available and patients have several hours to drink it. Usually a patient will have clear liquids the day of the preparation (day before the colonoscopy) and then take half of the prep about 12 hours before the procedure. The other half is done approximately 6 hours before coming in for the test the following day. Patients are encouraged to drink a lot of fluids and to continue clear liquids up until 4 hours before their scheduled procedure.
Smaller volumes of solution (e.g. MoviPrep®, Suprep®, Clenpiq®, Plenvu®) or pill preparations (e.g. OsmoPrep®) have also recently become available with similarly good outcomes to PEG for people who dread the thought of large volumes of liquid.
Alternatively, a tablet preparation of about 24 pills (Subtab®) is available and is also very effective for colon cleansing and is preferred by some patients. This preparation also requires that you drink adequate amounts of water to replace losses.
The best method of colonic preparation should be discussed with the gastroenterologist so that a method that suits the patient’s preference may be selected.
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