If you are at risk and take care of it,there is a 99.99 % percent chance you will never need more than an outpatient polyp snipped if even that.
If you get a tumor the first thing it does it block the bowel as an obstruction so you will need immediate surgery with the bowel removed and the bag,sounds scary i know but that's why prevention is so important.
Bottom line if you get cancer you get a bag (usually) and well you die too.