I got my j pouch because of stage 1 cancer that was almost undectable, but luckily my gastroenterologist saw something "funny looking", and off we went. I had no cancer symptoms before this, but had UC for many years, which was in remission most of the time.
After takedown I had an endoscopy every six months by the surgeon who created my pouch (under general anesthetic at my request). At the third year mark, I graduated to an annual endoscopy, but for the first time including a cat scan using dye, to check my organs. My pouch is four years old and functions very well.