I think the selling point of intermitten ADT (for my dad) is prolonged time before castration resistance. But from what i understand, there's no clear conclusion about intermitten ADT and prolonged time before castration resistance. If it's just for the purpose of reducing side effects, my dad probably will decide to keep it going without breaks.
There has been an evolution in the use of ADT drugs the past decade. It used to be Lupron (Trelstar is very similar) was used until castrate resistance, at which time adding chemo was tabout
the only option. During this period there was some experimenting to see if iADT could stretch out the effectiveness of Lupron. I do not know if much success came from these trials. Too shorten a long story, I will just say that drug trials have brought us to the point where it's known that the early addition of a second tier ADT drug like Xtandi to a Lupron type drug gives the most robust survival. This what your dad is getting.
I don't recall any guys on the forum doing intermittent use of these combination drugs. I don't think trials are happening for it, but I don't know.
Are the doctors suggesting the intermittent use of your dad's Trelstar and Xtandi?