Any rise is a worry Paul, but my friend has found that her hubby's rise has suddenly stopped and it's dropped, no treatment at all! John's is now 42 as the Radium treatment doesn't not have any impact on the PSA, so I'm hoping he'll get something added in shortly to tackle that rise. In the meantime, he's ok, obviously someone with cancer is unlikely to be bouncing up and down, but after nearly seven years, we will take what we can get!
Definitely base it lol on how you feel. Fingers crossed for you as always.