I am undergoing radiation as we speak. I had a positive margin after surgery. At first my psa was 0.0, but it then climbed to 0.1 for three consecutive readings. At that point I sought a second opinion, and we decided upon radiation.
From what I have figured out, the proper course of action given our staging is debatable in the medical field. My urologist would have preferred to wait until it climbs above 0.2. My radiation oncologist felt that the safest course of action would be radiation since my PSA was not zero.
And there are some folks here who didn't even wait a year but had radiation shortly after their surgery.
My one piece of advice would be not to hesitate to get a second opinion on your condition. I think the medical field is divided concerning the proper action given our staging.