Evidence from the National Polyp Study has shown clear evidence that removing adenomas (polyps) during a colonoscopy reduces risk for colorectal cancer significantly. There were more than 1,400 patients in the study who had colonoscopies and all existing polyps removed. After an average of six years, only five people developed colorectal cancer, all at an early stage. None died.
A colonoscopy allows the doctor performing the test to see the entire colon from the anus to the cecum and remove polyps.
The colonoscope is a thin, long, flexible instrument with a lighted lens or video camera at its end. Instruments to remove polyps or take samples of tissues for biopsies can be introduced through the scope. During colonoscopy, the scope is inserted carefully through the rectum and guided through the colon. Mayoclinic.Com has a video of a colonoscopy that illustrates the procedure.
Physicians who perform colonoscopies are usually gastroenterologists, but may be surgeons or, sometimes, specially trained family physicians. Locate a gastroenterologist who is a member of the American College of Gastroenterology or a find a member of the American Society for Gastrointestinal Endoscopy.
What’s the Procedure Like?
Before the colonoscopy begins, an IV needle will be put in your hand or arm for medicines to make you feel relaxed and sleepy. Most patients will have no pain during the procedure and will probably not remember the colonoscopy itself. If there is pain, additional medicine can be added to the IV. Patients with special needs may have an anesthesiologist present to administer deeper sedation. However, most colonoscopies are completed with moderate sedation administered by the endoscopist.
After your colonoscopy, you’ll need to rest for an hour or two in the recovery area until the sedatives have worn off. During this time, you will probably have to pass gas from air that was inserted during the procedure so the lining of the colon could be seen clearly. You will need someone to drive you home, but you’ll be able to return to your regular activities the next day.
Because the lining of the colon must be completely clean to provide the best view, bowel preparation the day before the colonoscopy is important. A clear liquid diet and strong laxatives will be prescribed for you. The laxatives will produce a great deal of watery diarrhea. Here’s more information on colonoscopy preps.
Depending on what is found during your colonoscopy, your doctor will recommend the right time for a follow-up colonoscopy. If cancer is discovered, you’ll be referred to a surgeon or medical oncologist for treatment.
Although it is rare, call your doctor immediately if you have severe abdominal pain, fever, bloody bowel movements, or dizziness or weakness after your colonoscopy.
Colonoscopy is not without risk. In a very,very small percentage of colonoscopies, the scope may make a hole (perforation) in the colon. There are also risks from sedation and from the preparation to consider.
Where Can You Go for More Information?
Audio and Slide Presentation: Sidney J. Winawer, lead author for the National Polyp Study, discussed The Role of Colonoscopy and Polypectomy in the Prevention of Colorectal Cancer during the AACR Frontiers in Cancer Prevention Research conference in December, 2007.
National Digestive Diseases Clearinghouse: Colonoscopy
Video of Katie Couric’s colonoscopy in 2000, credited for the “Couric Effect” that increased use of screening colonoscopy. Note: Katie is perhaps more awake and alert that most people would be. She says she wanted to be awake enough to ask questions during the taping.
American Society for Gastrointestinal Endoscopy has answers to many patient questions about colonoscopy on their site Screen4ColonCancer.Org.
Have a friend whose reached a fiftieth birthday? Send an email greeting card reminding them that screening prevents colorectal cancer.