@northoftheborder No, when I went back on therapy with Xtandi, my PSA (which elevated from 0 to 1.5 in the third 3- month period of ADT holiday) went back to zero and stayed there — 8 months now. One thing to note: one urologist told me that some percentage of people never experience castration resistance. They live to old age doing various hormone treatments and die some other way. I worried about that castration resistance as well, but the general idea of intermittent hormone therapy is to let your cancer wake up rather than to force it to mutate to survive, as I understand it.