I had been on Eligard/Lupon for a couple of years when my PSA suddenly started rising while Testosterone was flat at a low level.
Bone scans, MRI's, etc., indicated nothing going on. But the PSA numbers doubled every couple of months. I figured I was now "refractory", where the PCa no longer is testosterone-dependent, but my oncologist put me on Casodex, too, and that brought the PSA down significantly for a couple of months. To me, the "writing was on the wall" that the cancer was weaning itself off testosterone and "looking" afield, and that further HT would NOT be working. I went on Provenge, and later got radiation and am now on Taxotere. The addition of Casodex (that inhibits a slightly different type of testosterone than Lupron) to the Lupron bought me a couple of months, that's all. But don't be complacent and dither--this Gleason 9 monster is relentless and aggressive.