Open Margin Question

Hi,
I am still confused about something and hoping you guys would know, as its so hard to talk to my doctor! My PSA since RP in 11/15 has been <0.03, then on a new deeper testing the last 3 visits, each 3 months apart, my psa was 0.020, 0.021, and most recently 0.027. I go back in April and if it rises again my doctor advises radiation treatment, even though its still low, due to the slow rise.
My Gleason before and after surgery was confirmed at 6 (3+3). I had 1 positive margin of less than 1mm.
So I am assuming some cells escaped through this margin as a result?
My main question is this. If I do still have cells in there, would they still be Gleason 6, or is it a whole new ballgame and a dangerous situation? Are my statistics still the same as anyone having Gleason 6 (low risk) or am I at a higher risk of a poorer outcome? Do the cancer cells "change" once outside the prostate? My doctor is telling me the radiation would be to the prostate bed where it used to be, but I assume he needs to test that they really are there on not elsewhere before he shoots me with 9 weeks of radiation?
I am meeting a radiation oncologist next week for a preliminary introduction should I need it.
Thanks,
Tom

Thanks for the answer. But then that leads to my main concern. I have read many times that Gleason 6 does not spread (rarely in some articles). Is that still the case in my situation?
Tom