Hi Greg,
I can only describe my personal experience, so you'll have to try to assess what statistical relevance it has in relation to your own circumstances and concerns.
I was heading for the normal 20 sessions of EBRT when it became apparent that, after 3 attempts, the radio team could not get a sufficiently clear shot at my prostate , due to the configuration of my internal plumbing. Basically there was a loop of bowel in the firing line, and the onco's view was that the risks of collateral damage outweighed the benefits.
There was a bit of faffing around while I went back to square one in analysing my options, but to cut a long story short I had a second opinion and got access to a Top Gun MRLInac machine. This offered the opportunity of more accurate targeting, with real time location monitoring, and it was a 5 day rather than a 20 day blast.
The treatment itself was easy, and in the week after it finished I just had 2 days when I needed to be not far from a loo. Since then, and a year on, I have had no bowel problems at all.
Maybe I was just lucky; but given that bowel damage was certainly on the cards at one stage, I have been well pleased with the outcome. Of course, it may still be early days....
Best of luck with whatever course you embark on.