What is a Colonoscopy?

What is a Colonoscopy?

During your visit, talk to your doctor about a COLONOSCOPY

What is a colonoscopy?
A colonoscopy is an exam of the colon (large intestine or bowel) with a slim, flexible light tube called a colonoscope.  Your health care provider can use the colonoscope to get a clear, magnified view of the inside of your colon from the anus to the area near the appendix.

When is it used?
Colonoscopy is the most direct and complete way to see the entire lining of the colon.  It is usually done for early detection of colon cancer or polyps.

  • Prevention and early detection of cancer.  If you are between 50 and 80 old, your health care provider may recommend that you have a colonoscopy every 10 years.  If you have a personal or family history that increases your risk, your provider may recommend that you have the test more often. A colonoscopy can help your provider find and remove growths (polyps) before they become cancerous.  It can also allow your provider to detect cancerous growths early, when the cancer is easier to cure.

@Published by McKesson Health Solutions LLC
This content is reviewed periodically and is subject to change as new health information becomes available.  The information is intended to teach and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a health care professional.

Why get a screening colonoscopy?
Colorectal cancer is the third most diagnosed cancer in the US, and the second deadliest cancer in the US.  It is the third deadliest cancer worldwide.  When diagnosed at an early stage, before the cancer has invaded the colon wall or spread to distant sites, the chances of survival are much higher.  People who have had a colonoscopy in the past decade are less likely to be diagnosed with advanced colon cancer than those who haven’t been screened recently, according to a new study.  According to the American Cancer Society, about one in 20 people will be diagnosed with colon or rectal cancer during their lifetime.  This translates to a 71% lower risk of advanced cancer among people with a past colonoscopy.

What are the pros and cons of colon screening test?


  • Can usually view entire colon.
  • Can biopsy and remove polyps and is done every 10 years.
  • Can diagnose other diseases.

  • Can miss small polyps.
  • Full bowel preparation is needed.
  • More expensive on a one-time basis than other forms of testing.
  • Sedation of some kind is usually needed and will need someone to drive you home.
  • You may miss a day of work.
  • There is a small risk of bleeding, bowel tears, or infection

Fecal occult blood test (FOBT)


  • No direct risk to the colon.
  • No bowel preparation.
  • Sampling done at home.
  • Inexpensive.

  • May miss many polyps and some cancers.
  • May produce false-positive test results.
  • May have pretest dietary limitations.
  • Should be done every year.
  • Colonoscopy will be needed if abnormal.

Further information at following links: