Colonoscopy is perhaps the most effective method of diagnosing and also preventing colorectal cancer.  The way colonoscopy prevents colorectal cancer is by stopping polyps turning into cancers. 1 in 20 people will get colorectal cancer but if there is a close relative who also had the disease then the odds can be as low as 1 in 10.  After clearing out the bowels a colonoscopy can be performed under minimal sedation in 75% of patients, and more than 90% of the time the whole colon can be viewed.

As many as 1 in 3 people get polyps (which are wart like growths) in the large bowel.  Colonoscopy detects over 90% of polyps, which can be destroyed or snared.  It is important you know your surgeons major bleeding and perforation rate for this procedure and the risk to benefit ratio is discussed beforehand.  I carry out over 250 colonoscopies every year and currently have a 0% perforation rate.