Colorectal Cancer Screening

A colonoscopy is the inspection of the entire large intestine (colon) using a long, flexible, lighted viewing scope (colonoscope), which is usually linked to a video monitor. A colonoscopy is performed to screen for cancer or to investigate symptoms, such as bleeding.

Preparation for the test includes emptying the bowels ahead of time using a laxative. You’ll be given medicine to relieve pain and to make you drowsy. A doctor will remove any small growths (polyps) found or collect a tissue sample (biopsy) from any abnormal area. The tissue is then analyzed by a pathologist.

Colonoscopy may be done to:

• Check for polyps as a screening test for colorectal cancer.
• Check for the cause of blood in the stool or rectal bleeding.
• Check for the cause of chronic diarrhea.
• Check for the cause of iron deficiency anemia.
• Check the colon after abnormal results from a test, such as a stool test or CT scan.
• Watch or treat colon conditions such as inflammatory bowel disease (IBD).
• Check for the cause of long-term, unexplained belly or rectal pain.

• A colonoscopy may be done in a doctor's office, clinic or hospital.
• Hospital procedures are generally performed in a dedicated endoscopy suite. 

There is a small chance for side-effects from a colonoscopy. The scope may tear the colon or cause bleeding.

The test usually takes 30 to 45 minutes. But it may take longer, depending upon what is found and what is done during the test.

You will need to take off most of your clothes. You will be given a gown to wear during the test.

You may lie on your left side with your knees pulled up to your belly. You will be given medicine during the colonoscopy to make you comfortable and help you sleep during the procedure. Next, the doctor will insert a thin, flexible colonoscope in your anus and move it slowly through the rectum and into your colon. Air will be used to inflate your colon so the doctor can see the lining of the colon on a monitor.

During the test, you may get a pain medicine and a sedative put in a vein in your arm (IV). These medicines help you relax and feel sleepy. You may not remember much about the test.

Your doctor will look at the whole length of your colon as the scope is gently moved in and then out of your colon. You may be asked to change your position during the test.

The doctor may also collect tissue samples (biopsy) or take out growths. Typically, people don't feel anything if a biopsy is done or if polyps are taken out.

The scope is slowly pulled out of your anus, and the air escapes. Your anal area will be cleaned with tissues. If you are having cramps, passing gas may help relieve them.

After a colonoscopy, you'll stay at the clinic until you wake up. You can then go home, but you'll need to arrange for a ride. Your doctor will tell you when you can eat and do your other usual activities.

Your doctor will talk to you about when you'll need your next colonoscopy and help you decide how often you need to be checked. This will depend on the results of your test and your risk for colorectal cancer.

After the test, you may be bloated or have gas pains. You may need to pass gas. If a biopsy was done or a polyp was removed, you may have streaks of blood in your stool for a few days. Problems such as heavy rectal bleeding may not occur until several weeks after the test. This isn't common. But it can happen after polyps are removed. Call your doctor’s office if this occurs.

Drink a lot of fluid after the test to replace the fluids you may have lost during the colon prep. But don't drink alcohol and consult your physician to learn when it is safe to resume.

Check with your doctor to see when it is safe to take aspirin and nonsteroidal anti-inflammatory drugs again.

The results of a colonoscopy may be normal or abnormal.

Normal: The lining of the colon looks smooth and pink. It has a lot of normal folds. No growths, pouches, bleeding or inflammation are seen.

Abnormal: Some abnormal findings include hemorrhoids, polyps, cancer, one or more sores (ulcers), pouches in the wall of the colon (diverticulosis) and inflammation. A red, swollen lining of the colon (colitis) may be caused by infection or inflammatory bowel disease. If your doctor took a sample of tissue (biopsy) during the procedure, it will be sent to a lab for tests.

Before your colonoscopy, call if:

• You have questions or concerns.
• You don’t understand how to prepare for your procedure.
• You are having trouble with the bowel prep.
• You become ill before the procedure (such as fever, flu or a cold).
• You need to reschedule or cancel.

After your colonoscopy, call 911 if:

• You passed out.
• You pass maroon or bloody stools.
• You have trouble breathing.
• You have pain that does not get better after you take pain medicine.
• You are sick to your stomach or cannot drink fluids.
• You have new or worse belly pain.
• You have a fever.
• You cannot pass stools or gas.
• Watch closely for changes in your health and be sure to contact your doctor if you have any problems.