The good news is that the pouch is made of small intestine, and cancer of the small intestine is very rare. Cancer of the rectal cuff (the bit of colon left in during most pouch surgeries) does occasionally occur and is probably worth screening for given your history. A DRE (digital rectal exam) could potentially miss part of the rectal cuff, and would definitely miss dysplasia, so I think many folks would opt for something like a yearly pouchoscopy with biopsies. It’s a fairly quick procedure that can be done with a pretty easy prep, and most folks opt to do it without sedation. An MRI would be a waste of time and money.
Sometimes pouch surgery is done by hand-sewing the pouch to the anus, which pretty much eliminates the rectal cuff. If that’s the procedure you had then your risk of a cancer recurrence is probably much lower.