On another thread, there was a link that lead me to two studies (UCLA, Johns Hopkins) that suggested that on the uPSA, 0.03 was a threshold for predicting biochemical recurrence [BCR]. My urologist, though, agreed approximately with @web265, saying that we would act when 0.1 was reached (on the uPSA test assay.) So what this tells you is that there is some possibility you will be facing BCR in the future, but it's still perhaps a couple years away. Here's to a good journey in the days yet to come!
As others have stated, at these lower levels, the doubling rate has not been found predictive, to the best of my knowledge.