Lupron Treatment Duration: How long were you on it?

I have been diagnosed with Grade 3 prostate cancer with a 4 + 3 Gleason score of 7. This after having 2 PSA scores last year between 4 and 7. The cancer has not spread to the bones. I have received two Lupron injections 3 months apart and will complete 28 radiation treatments in the next couple of days. No surgery. I have tolerated the Lupron shots well with few but manageable side effects. I have an appointment to receive a third Lupron shot next month. My first PSA test after completing radiation won't be scheduled for 3 months. From researching Lupron, it appears that this is used for advanced stages of prostate cancer. From what I was led to believe, I was not advanced. My question: How long and how many Lupron shots might I need to go through? I will have this discussion with my urologist hopefully before proceeding with the next shot. Thanks for any information provided by the group.