What Is a Colonoscope?

How the Visual Technology Is Used to Prevent Cancer

Table of Contents
View All
Table of Contents

A colonoscope is a long, thin, flexible instrument that is inserted into the anus for a visual inspection of the colon and rectum. It has a digital camera and light source mounted at the end and is used to perform a common diagnostic procedure known as a colonoscopy.

A colonoscopy can be performed in a hospital or clinic setting. Persons undergoing the procedure are typically sedated so that they experience no discomfort. During the exam, live digital images are displayed on a video monitor to help guide the investigation. Still images are commonly taken for up-close examination or to help make comparisons to earlier images.

Surgeon controlling colonoscope

Wicki58 / Getty Images

A colonoscope is used by a physician specially trained in the technology, including gastroenterologists and colorectal surgeons. Some of the medical conditions diagnosed with a colonoscope include:

Colonoscopy and Cancer

A colonoscope is considered a frontline tool to assess and prevent colorectal cancer.

If during the course of a colonoscopy, the physician spots an abnormal growth of tissue, known as a polyp, he or she will typically use the colonoscope to remove it for further investigation. While most polyps are benign, some have the potential to turn malignant (cancerous) as they grow larger.

To remove the polyp, the doctor will use an electrical attachment on the colonoscope, known as the snare loop, to simultaneously excise the polyp and cauterize the wound. Because there are few nerve endings in the intestines, the procedure is relatively painless. This technique may be referred to as a "hot snare." Other techniques include a biopsy, cold forceps, hot forceps, and cold snare.

Once the polyp is extracted, the biopsied tissue will be sent to a lab to assess whether the cellular structure is consistent with cancer or precancer. In some cases, the doctor may also use the colonoscope to tattoo the inside of the colon so that the site of the biopsy can be rechecked during future examinations.

Risks and Limitations

No procedure is without its risks, but those associated a colonoscopy are considered small with the benefits of treatment far outweighing the risks. The most common risks include:

  • An adverse reaction to the sedative
  • Bleeding from the site of the biopsy
  • A tear or perforation the colon or rectum

At the same time, while the benefits of a colonoscopy can be significant, the procedure itself is not without its limitations or shortcomings.

By and large, the early detection of precancerous growths can greatly reduce a person's risk of developing colorectal cancer. The problem is that many of these growths are not easily spotted as the colonoscope snakes its way through the intestines. This is especially true for right-sided cancers that can often evade detection as they are tucked into the folds of the intestines. However, overall colonoscopies are recommended as the gold standard for detection and prevention of colon cancer.

A 2010 study from Germany, comprised of 3,600 male and female participants, concluded that the current colonoscopic technologies differed in how effective they are in spotting cancer. According to the research, colonoscopy reduced the risk of left-sided cancer by 84 percent but only reduced the risk of right-sided cancers by 56 percent.

What This Should Tell You

To ensure your own personal good health, many specialists today advise that you not take anything for granted and request visual evidence that a complete examination has been performed. You can do this by requesting several photographic images, including one of the cecum (the part of the large intestine furthest from the rectum).

According to guidelines issued by the American Cancer Society, all adults over 45 should have a colonoscopy as part of a routine exam with investigations repeated every 10 years. Persons at an increased risk may need one every three to five years, while persons with a family history of colorectal cancer may need to start earlier.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.