Treatments and Procedures » 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.
A colonoscope is a flexible and steerable instrument to evaluate the entire colon (large intestine). The large intestine is approximately 3 – 4 feet long. A colonoscope is engineered such that biopsies of suspicious areas can be obtained, and polyps (which may turn into cancer) can be removed.
Yes. Colonoscopy accomplishes this by detecting and removing polyps, and detecting early cancers. Recent data show that both the number of new cases of colon cancer (incidence) and deaths from the disease are decreased when colonoscopy is performed according to established guidelines (see Question 11).
The most common reason patients cite for not getting a colonoscopy is that their doctor did not discuss it with them. The next most common reason is fear or avoidance of the preparation (“prep”), which involves taking a laxative which causes temporary diarrhea for several hours. In addition, many people are simply unaware that they need colon cancer screening.
No, colonoscopy is usually not painful! Almost all colonoscopies can be performed using “intravenous sedation” or “twilight sedation” in which you are very drowsy, but comfortable and still breathing on your own. The most common type of sedation also has a mild amnesiac effect, so most patients do not even remember the procedure! Your doctor can discuss with you the best form of sedation to suit your needs.
Medicare (and most third party payers) will pay for colonoscopy for colon cancer screening, thanks to the hard work of advocacy groups and the efforts of national organizations such as the American College of Gastroenterology (ACG). Regrettably, a recent study showed a low compliance rate for screening (less than 30%) among Medicare patients.
CRC Risk Factors
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, and excessive alcohol consumption. Your doctor is in the best position to discuss whether your personal or family history suggests one of those conditions.
If you have no colorectal symptoms, family history of colon cancer, polyps or inflammatory bowel disease you should have your first exam at age 50 whether you are a man or a woman since colon cancer affects both EQUALLY! Recent evidence suggests that African Americans should begin screening earlier at the age of 45.
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.
For patients with ulcerative colitis involving the entire colon and patients with Crohn’s disease, screening for colon cancer should begin 8 – 10 years after the initial diagnosis is made.
Yes, there are alternative methods to examine the colon, but none are considered more accurate at colon cancer and polyp detection than colonoscopy. They include:
- A flexible sigmoidoscopy and a barium enema (an x-ray examination of the colon after it has been distended by barium, a contrast agent, following a preparation with a Fleet® Enema or Fleet® Phospho-soda).
- Computerized tomography (CT), a test that takes pictures of the inside of the colon, can also be done. This is called CT colography or “virtual colonoscopy”. Like conventional colonoscopy, this test requires a full preparation the day before the exam (liquids and possibly enemas). This test, however, involves radiation exposure which may increase your long term risk of development of cancer.
If any of the above tests suggest the presence of polyps or cancer, a conventional colonoscopy (and a second preparation) will be required.
Fecal Occult Blood Testing (FOBT), is a test whereby stool is examined for minute amounts of blood loss (possibly from polyps or cancer) by way of a chemical reaction resulting in a color change. While FOBT is not a test to examine the colon, it is recommended annually to individuals over age 50. If occult blood is found in the stool, a follow up colonoscopy will be necessary.
For colon cancer screening, it should be noted that colonoscopy has the highest sensitivity and is the only test that is both diagnostic and therapeutic.
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 in the late afternoon or that evening. The other half is done approximately 5 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 2 hours before their scheduled procedure. Before going to bed, many doctors also prescribe a laxative pill (e.g. Dulcolax®) that helps with the evacuation process.
- Smaller volumes of solution (e.g. MoviPrep®, HalfLytely®) 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.
- Another preparation involves a phosphate solution (called Fleet® Phospho-soda) which consists of two (2) rounds of phosphate rich liquid of 45ml each the night before and day of the exam. It is essential to drink at least 2 quarts of water with these preps to replace losses.
- Alternatively, a phosphate tablet preparation of about 30 pills is available and is also very effective for colon cleansing and is preferred by some patients. This preparation also requires that you drink at least 2 quarts of water to replace losses.
Phospho-soda® prep should be avoided in patients with significant heart or kidney problems, in elderly patients who have difficulty maintaining hydration and with caution in patients with significant liver problems.
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.
Yes, but potential complications are associated with virtually every form of testing done in medicine. Clearly, colonoscopy has been found to be extremely safe when performed by a well trained physician such as a gastroenterologist. Although quite rare, most complications are related to sedation administration (cardiac and respiratory problems); the colon may also become partially torn (perforated) and this may require surgery. Rarely, bleeding from polyp removal or from the procedure itself may require additional treatment such as hospitalization and/or blood transfusions. As one reads about these procedures, the reader should weigh these low risks against the far more frequent complication of developing colon cancer if appropriate testing is NOT done.