Don't fear the colonoscopy. Doctors seem to like doing it under GA, but I insisted for my last that I wanted to be awake and watching the procedure on a monitor. Medium short term discomfort, but a fascinating exercise, with a wonderful 'release' afterwards (you are pumped full of air). The most unpleasant bit was the clearing of the system for the day before, and not being able to eat or drink anything but water or clear soup.