Colonoscopy is a common exam that doctors use to detect changes or abnormalities in the large intestine (colon) and rectum.
During the exam, a long flexible tube (colonoscope) is gently inserted into the rectum. Using a tiny video camera poised at the tip of the tube, your doctor views the inside of your entire colon. Your doctor may also use a second device inserted through the same tube to remove polyps or tissue samples during the colonoscopy.
A colonoscopy is typically recommended to investigate gastro-intestinal symptoms (pain, bleeding, chronic constipation or diarrhea).
It is also the gold standard exam to screen for colon cancer. If you're age 50 or over your doctor may recommend a conoloscopy every 10 years, sometimes sooner given other factors, such as a family history. There are additional options for colon cancer screening, and you're encouraged to discuss your options with your doctor.
For a helpful overview of the colonoscopy procedure, we recommend this video:
Why Colonoscopy is Important
One of the most important reasons for a colonoscopy is to find and remove polyps from the colon. These are small growths that are typically asymptomatic (neither patient nor doctor know they're there before the colonoscopy).
Finding and removing these lesions is important in preventing colon cancer. Most polyps take years to become cancerous, and a single colonoscopy can catch many of them before they have a chance to become malignant. The best way to treat colon cancer is to find it and remove the polyps before it ever gets started. Because colonoscopy is safe and easy, it has become an indispensible tool in preventing colon cancer.
Preparing for a Colonoscopy
Before a colonoscopy, you need to clean out or empty your colon as residue would obscure your doctor's view during the exam. Your doctor will give you precise instructions, but in general you can expect them to include these basic steps:
During Your Colonoscopy
Once your preparation is complete and you've checked into the hospital's Admitting Department, you'll change into a hospital gown. You'll also be mildly sedated just before the exam for your comfort. This medication is often given intravenously.
You'll lie on your left side as the exam begins, and that may be the last thing you remember before you wake up. With your knees drawn toward your chest, your doctor will insert the colonoscope into your rectum. The scope is long enough to view the entire length of your colon and contains a light and a tube through which the doctor will lightly pump air or CO2 to inflate your colon for optimal viewing of the colon tissues. Your doctor will slowly draw the tube back out and inspect the lining of your colon during this time.
The colonoscope contains a tiny camera that may be used to take images of specific tissues or suspected abnormalities. Your doctor may also insert an instrument through the same tube to take tissue samples or remove polyps. These tissues are sent to a lab for biopsy after the exam.
The entire colonoscopy usually takes 20 minutes to an hour. Your doctor will discuss results with you personally following your exam.