I don’t know but it is worth asking your doctors these questions.
To be honest, a rise from 0.04 to 0.08 in a year could be the result of new testing equipment, a change of laboratory or the recalibration of existing equipment. Also, with a rise from 0.01 to 0.08 over 4 years, even if it is a recurrence it is a very small cluster of cells and not very active; it has taken my dad 19 years to get to 0.3 and the urologist predicts it will be another 25 years before it kills him.