Until recently, flexible sigmoidoscopy was the way we performed screening examinations for colon (large intestinal) cancer. Sigmoidoscopy coupled with stool Hemoccult testing, which is testing for blood in the stool, was the standard of care. Recently, most organizations have accepted the fact that the appropriate screening should entail viewing the entire colon. There are many ways of doing this, including barium enema, colonoscopy, and newer techniques that are not yet commonly available.
Colonoscopy entails taking a very flexible, thin, lighted instrument, very gently passing it around the entire colon, otherwise known as the large intestine.