2. What is the difference between flexible sigmoidoscopy and colonoscopy?Flexible sigmoidoscopy is a faster procedure compared to colonoscopy. It does not require sedation and the person can return to work soon after the procedure. In contrast, colonoscopy takes longer time and requires sedation. Some people may prefer to be sedated, thus this could be an advantage in such patients. Colonoscopy permits examination of the entire colon whereas in sigmoidoscopy, only the lower portion of the colon is examined. Thus a number of cancers especially those on the right side could be missed in flexible sigmoidoscopy. Flexible sigmoidoscopy should be repeated every 5 years whereas colonoscopy every 10 years.