Hi Gaz,
Welcome to the forum. It's a shame you've had to join us, but I'm glad you have.
I'm in a similar position to you. I had RARP last February. Three PSA checks since, <.02, <.05 and <.02 again. The slight central rise was due to being tested at a different lab. All results were classed as undetectable all were lower than the lowest level the labs could test to.
I'm due another result this week. I hate PSA test times, they do my head in.
Psychologically any rise, no matter how miniscule, is disconcerting. However, I was told that they would only consider other treatment, if I got three consecutive rises, or it reached 0.2.
Dave, as usual, has explained everything clearly. As he says, it would be helpful if we had a few more details of your results. If you intend contributing regularly it might help if you completed a more detailed bio on your profile.
Anyway, nice to meet you and best of luck for the future.
Adrian