What is a Colonoscopy?

A colonoscopy (lower endoscopy) is a procedure using a flexible camera to look inside your colon, rectum, and anus. The purpose is to look for any abnormal growths (i.e. polyps), areas of bleeding, altered anatomy, and cancer.

An additional word before the word “colonoscopy” is used to describe why you are undergoing the procedure, but it does not change the way your colonoscopy is performed. Below are the different descriptive words you may see

• Screening colonoscopy – performed because you need it based on your age or family history (you are “due” for one) so that polyps or colorectal cancer can be ruled out. Screening is recommended because it can detect polyps or cancer in the colon that you would not have known about otherwise. In other words, just because you feel fine does NOT mean your colon is clean and free of underlying growths/cancer.
• Diagnostic colonoscopy – performed because you have symptoms that could be a sign of disease in your colon or rectum. Symptoms could include abdominal cramps, bleeding, changes in your stool habits, or unintentional weight loss
• Surveillance colonoscopy – usually done for those that have had polyps or a history of colorectal cancer

Yes. In the majority of cases colonoscopies are performed under intravenous (IV) sedation medication that lower your level of consciousness just enough so that you do not feel or remember the procedure. You will still be breathing on your own, and an endotracheal (breathing) tube is rarely ever needed. 

It is best to have polyps removed in their entirety as it gives us the strongest confidence to know whether there are cancer cells or not. It also lowers the chance of leaving a piece of it behind to grow back. This happens during your colonoscopy typically with an lasso instrument called a snare or a biopsy forceps instrument.

Sometimes a polyp can be too big to safely excise without damaging the wall of your colon. In these cases a piece of it is taken for biopsy purposes to evaluate for cancer cells, and you may be referred to a specialist who can utilize advanced techniques to remove large polyps. Otherwise, you may be counseled to undergo surgery to remove the segment of colon containing the polyp.

If at any point you are found to have cancer cells in any of the biopsy samples, a tailored discussion must be had with a colorectal surgeon.

• Missed pathology - colonoscopy is the best test to evaluate the colon, but it is not perfect. There is a chance a polyp or other abnormality might be missed and not identified
• Bleeding - if a biopsy is performed during the colonoscopy, there is a rare chance of ongoing bleeding that may require a hospitalization, blood transfusion, repeat colonoscopy, colon resection, or other procedures.
• Perforation - aggressive manipulation of the colonoscope or excess air insufflation inside the colon could lead to a hole in the colon wall that would require emergency surgery to fix the hole. This is rare with a 1:1000 chance of happening.