Hi Kevan,
If you look at my post 'EBRT & Salvage HDR Brachytherapy' you will see we were discussing this very point earlier this month.
My own consultant, set me a new target PSA of 0.6 and suggested that I should go back on HT if my next PSA test exceeded that.
However I then had an annual follow up call from the consultant who gave me salvage HDR Brachytherapy. The call was actually from his assistant, she said that anything under the nadir+2 threshold was absolutely fine, and that she anticipated a PSA in low single figures, perhaps 2, 3 or 4, she was quite alarmed to hear that we were considering HT with a PSA less than 2 and told me to wait until my PSA was in 'double figures'.
Obviously it isn't easy to reconcile two bits of conflicting advice, but there are some useful posts on that string, if you look for it under 'Treatment' you will find it around 3rd March.
:)
Dave