I used to have a bunch of 'friends' that didn't treat me very well. about
20 years ago I just dumped the lot, keeping the friends that treated me fairly. Those are still with me, as are a whole bunch of newer friends.
My view (now that I am sorta "old") is that life is short and I won't invest time and energy into relationships with people that make me feel bad, criticize me or try to take advantage of me.
As for discussing PCa....some folks I discuss that with, most I do not. It depends on my relationship with the person in question. The cancer is like my 'Harley knee' - it does not define me as a person. Rather, my art, my Taekwondo, meditation, music, my distance running, my excellent relationship with my wife, son and lovely lady Labrador - these are what is important to me.
The rest, as they say, is just passing water under the bridge.