A colonoscopy is a specialized test that lets the doctor see the inside lining of the colon and rectum using a colonoscope (scope). The scope is a long, flexible tube about the width of a finger with a light and tiny video camera on the end.

The scope is put through the anus into the rectum and colon. Pictures are taken of the lining of the colon and can be seen on a computer screen. This helps the doctor to have a clear view and to check if there are any polyps or abnormal growths.

If a small polyp is found it can usually be removed during the test using special tools that can be passed through the scope. The removed polyp is then sent to the lab to check if it has any areas that have changed into cancer. This is because some small polyps can become cancerous over time.

• A polyp or abnormal growth that is too large to be removed and/or appears to be cancer may need to be removed at a later date. A small piece of it will be removed (biopsied) through the scope. The sample will be sent to the lab to see if it’s cancerous, a non-cancerous growth or something else.