Colonoscopy and Colorectal Screening

Photo of surgeon and nurse reviewing a screening test

Listed below are frequently asked questions that will provide more in depth information regarding the various tests and procedures associated with colorectal cancer screening. Click on a question to see the answer.

What is a colonoscopy?

A colonoscopy is a very safe outpatient procedure intended to examine the colon and rectum (look for inflammation, polyps, cancer, vascular abnormalities, etc.) with a long and flexible instrument called a colonoscope. During a colonoscopy biopsies (to obtain a tissue diagnosis) and polypectomies (polyp removal) are routinely performed.

Who should have a colonoscopy?

It is recommended that a colonoscopy be routinely performed on adults 50 years of age or older as part of a colorectal cancer screening program. However, a colonoscopy can be recommended at a younger age especially for those individuals who have a family history of colon cancer. A colonoscopy should also be considered if you develop rectal bleeding, abdominal pain, severe constipation, unexplained diarrhea or mucous discharge.

What preparation is required for getting a colonoscopy?

Prior to getting a colonoscopy it is very important that the colon be thoroughly cleansed and emptied. This is achieved through the use of a bowel cleansing solution that is prescribed to you by your doctor. You must follow the instructions for the cleansing solution and all other preparation instructions (i.e. dietary and medication intake, etc.) carefully to insure that the colon is as cleansed and empty as possible. Inadequate preparation may prevent the performing doctor from having the clearest and most accurate view during the procedure which could result in the colonoscopy needing to be repeated at a different time.

Click on the links below to view our detailed preparation instructions which vary slightly depending on what part of the day you are scheduled for your colonscopy.

How is a colonoscopy performed?

A colonoscopy usually takes about 30 minutes and is performed in an outpatient endoscopy unit setting following a thorough bowel cleansing one or two days prior. If needed a patient may be administered intravenous sedation during the procedure. After a routine rectal exam is performed an instrument called a colonoscope is passed through the rectum and into the cecum (the part of the bowel where the small intestine joins the large intestine) to look for any abnormalities which if found may be cause for a biopsy or polyp removal. Following the procedure if a sedative was administered the patient will be restricted from driving for 24 hours; however, there are no restrictions on diet.

What are the risks associated with having a colonoscopy?

Statistically, about 75% of patients will experience minimal discomfort during the procedure resulting mostly from insufflated air. To help with any pain or discomfort most patients will receive intravenous sedation during the procedure which, as with any anesthetic, does run a risk of complications from an allergic reaction. There is also a risk of the patient experiencing intestinal bleeding. Risks can be increased if a poor cleansing preparation is done to include a decreased ability to detect small polyps during the procedure.

What are the benefits of having a colonoscopy?

Colonoscopy is the best available tool for detecting and removing polyps and other mucosal abnormalities thus avoiding more invasive abdominal surgery in the future. The removal of these polyps and abnormalities is a crucial step in the prevention of colorectal cancer.