What to expect during a colonoscopy

Colonoscopy is a potentially lifesaving test that can detect colorectal cancer early, when it’s most curable. Yet the thought of the procedure leaves most people squeamish: Approximately 50 percent of people who should get the test don’t because of fear of discomfort or embarrassment.

Perhaps you’re one of those people putting off this lifesaving screening. Knowing what to expect, discussing any concerns with your doctor and talking to others who’ve had the procedure may help lessen your anxiety.

Getting ready

Generally, on the day before the exam, you’ll need to begin preparing your colon by clearing out your lower bowels of stool and fluids. Your colon must be completely clear of anything that can block the view of the colorectal lining for test results to be accurate. Your doctor will ask you to take an oral laxative or drink a special cleansing liquid—and stay near a bathroom. He or she may also instruct you to:

• take enemas

• avoid eating solid foods and drinking opaque liquids

• drink only clear, nonalcoholic liquids like tea, water, clear broth or juices

• avoid red liquids, which may make tissue appear bloody

• stop taking iron pills or medications containing iron, which can change your colon lining’s color

The procedure

Before your colonoscopy, you will be given a sedative and pain medication or anesthesia to minimize any discomfort. During the test, which will last from 15 minutes to an hour, you will lie on your left side while a doctor inserts a long, thin tube (about as wide as a finger) called a colonoscope into your rectum. He or she then inflates your colon slightly by pumping air through a channel in the colonoscope. As this is being done, you may feel stomach cramps or pressure. The colonoscope is equipped with a fiber-optic light and tiny video camera, so your doctor can view images of your entire colon as they are transmitted to a TV screen.

If your doctor finds polyps—tissue projecting from the sides of your colon—he or she may remove them during the exam or take a biopsy. (Neither procedure should cause any pain.) Your doctor may schedule you for later surgery to remove large polyps. Polyps are usually not cancerous, although they have the potential to become cancerous as they grow.

After the exam

Once the exam is over, you may be a bit woozy from the sedative or anesthesia, so be sure someone can drive you home. You’ll want to stay home and relax while the medicine wears off, which could take up to 24 hours. It’s normal to experience gassiness or bloating (walking around may help) or slight bleeding with your first bowel movement. Call your doctor if you have a fever or abdominal pain or if you pass blood or blood clots.

Your doctor will decide how often you’ll need colonoscopy screenings based on whether polyps were found, what kind they were, whether the exam permitted a complete view of your colon and your risk factors.

A colonoscopy is the most accurate test available for detecting colorectal cancer and precancerous polyps. By the time signs or symptoms of colorectal cancer usually appear, the disease has progressed and your chances of being cured are lower. That’s why it’s critical to get routine screenings, which help detect the disease before symptoms appear and improve your chances of recovery.