I had salvage radiation and six months Lupron in 2019. My testosterone came back to 400 in three months, but my cancer came back in two years. I then had five radiation treatments to a lesion on my sacrum and three years on Lupron and Abiraterone. My PSA has remained undetectable for over four years, but my testosterone is only slowly returning in the one year that I have been off ADT. We are all unique and nobody knows how our bodies will react, but your doctor is probably more interested in stopping the spread of your cancer than your testosterone levels and the difficulties no or low testosterone brings. I am 74 and otherwise healthy, eat healthy and exercise daily for at least an hour.