Hey Frizzle,
We were in the same situation as you. Jim went intermittent after a year on lupron. PSA started rising rather quickly. We decided to try the c11acetate scan to see if targeted radiation might work if lymph or bone mets could be located.
Scan was clear at .04 PSA.
We then pursued the Prostvac/enzalutamide trial at the National Institutes of health in Bethesda, MD. Jim was randomized to the arm that received both Enza and the immunotherapy!! Its been a wild ride with lots of trips to DC. But the 3 months of enza knocked the PSA to .01 and now we wait to see if the prostvac will keep the bugger's at bay.
Yes, lupron and adt3 could keep working for years but this opportunity to receive immunotherapy early in disease progression convinced us to try the trial.
If you're in MN I believe DR.Kwon at Mayo in doing a c11 choline scan.
I'd be happy to share additional info if you email. We have the 32 page consent form which makes great bedtime reading
http://www.clinicaltrials.gov/ct2/show/NCT01875250 Marie and Jim