I was on leuprolide (Lupron, Firmagon, Eligard etc) chemo for 2 & 1/2 years. When I went off it I got regular blood tests to observe my recovery from that. It took 2 & 1/2 years for my body to return to its new normal. That is why they do intermittent leuprolide chemo.
Some med professionals say that the average lifespan of a prostate cancer stem cell is about
3 years, so the theory is that if they keep you on leuprolide chems for that long, all of the cancer stem cells will die off and you will be cured. That didn't happen for me so my guess is that the 3 year thing is hooey.
Also - my 2 & 1/2 years of leuprolide chemo killed off both of my testicles. 1 never came back on line and the others' testosterone production dropped to 160 ng/dL before my current round of leuprolide. The longer you are on leuprolide chemo the greater the chances of killing off some vital organs (hypothalamus, pituitary) or inducing a serious medical condition (heart attack, type 2 diabetes etc).
I waited to get an axumin PET until my PSA was over 3.0 so there would be enough tumor mass to register on the scan so bear that in mind. It won't fire back up bigtime right away if you stop leuprolide chemo.
Further, some folks think that staying on leuprolide inhibits ONLY the hormone-sensitive cancer cells while allowing the more advanced 'castrate resistant' cells to outcompete them as they remain unaffected.
Just some stuff to consider.