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What is colonoscopy?

A colonocope is a flexible tube like device with a camera for visual inspection of the colon (large intestine), which includes the rectum, sigmoid colon, descending colon, transverse colon, ascending colon, cecum and terminal ileum.

If a small polyp is found during colonoscopy, the endoscopist can immediately remove it, and send it for pathology review. If other abnormalities are found, a biopsy can be taken and also sent for pathology review.

When is colonoscopy needed?

Colonoscopy can be performed for screening or for diagnostic evaluation. Screening is for individuals who do not have symptoms, and the procedure is used to find asymptomatic polyps and early colorectal cancer (CRC). International guidelines recommend CRC screening, such as by colonoscopy, starting at 50 years old in general. CRC screening has been shown in multiple studies to reduce the risk of CRC, by removing polyps and preventing their progression to CRC.

High risk patients, particularly those with a first degree relative (parents, siblings or children) with CRC, should be screened earlier at 40 years old. Recent research conducted at the Chinese University of Hong Kong has also shown siblings of patients with high risk adenomas are also at higher risk of developing polyps, and likely benefit from screening.

Colonoscopy is also performed for diagnostic evaluation of symptoms such as rectal bleeding, change in bowel habits, abdominal pain, tenesmus, unexplained weight loss and anemia,which may be symptoms of CRC.

How to prepare for a colonoscopy?

Once a physician has recommended colonoscopy, detailed preprocedure instructions, which include dietary restriction (low residue diet), a colon cleansing routine and use of prescribed medications, will be provided. The purpose of this preparation is to cleanse the colon of stool to ensure a complete and accurate examination. It is important to follow these instructions closely. Patients are recommended to be accompanied by a family member or friend for their safety after bowel preparation.

What happens during colonoscopy?

Prior to the examination, intravenous sedation will be administered to reduce patient discomfort and anxiety. The flexible colonoscope will then be introduced through the anus to start the examination, which usually takes approximately 30minutes to perform. If a small polyp is found during colonoscopy, the endoscopist can immediately remove it with forceps or a wire loop, and send the specimen for pathology review. Colonoscopy is in general well tolerated, and there should be no pain with polypectomy.

What happens after colonoscopy?

A report of the colonoscopy findings will be provided. (we did provide the full colonoscopy report after the exam finish, but patient need to wait for histology report, if any) If polyps or biopsies were taken during colonoscopy, pathology results will be provided within a few weeks as soon as possible. Patients in general can leave the endoscopy center the same day, and are recommended to be accompanied by family members or friends. Patients should avoid operating heavy machinery, driving or signing any important document or contract for the rest of the day.

What are possible risks of colonoscopy?

Colonoscopy by experienced endoscopists are in general well tolerated and safe. Risks of serious complications are less than 1%, and include cardiopulmonary complications, perforation and bleeding, etc. If these events occur, admission for monitoring, further investigations and treatments will be prescribed per standard practice.