It's astonishing that some doctors talk of the morbidity that the PSA check can cause and deem it a reason not to do the checks. I've always thought that was a bizarre bit of logic. Let's not put red warning lights in aircraft in case we upset the crew with false warnings.
I've not heard of low dose brachytherapy, though yours was a low Gleason. I'm sorry to hear of your bad news.
Mine was 4 - 3, the bad way round, and right on the borderline for the procedure. Given the choice again, I'd go with the same procedure. The only side-effect I had was 'Bowl-hurry'. 1 in 500 chance was stated, though I felt at the time it was a figure plucked out of the air. All it meant was the signal that I wanted to go did not give me much notice. I watched my wife and daughter ride the London Eye from the embankment, there was no way that I could be trapped in a place like that. Commuting to Texas meant a full Picolax procedure 36 hours before flying.