Jerry,
I have had the 'roids since a rectal fistula a few (~5) years ago. When We did all the scheduling for DaVinci surgery, and then for IGRT, they sent me to a colo-rectal guy for pre-approval.
He commented that my rectum looked like a patchwork quilt. There were serious compliments for the surgeons work, but the warning that radiation would be problematic.
Short version - a past (before radiation) problem with significant rectal bleeding every 8-12 months is now (6 months post-IGRT) every 4-6 weeks. I take a lot of antibiotics, and hope it will improve.
The connection to radiation appears to be there, in my non-physician's view.