Hello Zach,
I am on Lupron which is very similar to eligard. It will reduce the PSA and shrink the prostate prior to treatment. The hot flashes seem to diminsh over time and I just live with it. To my knowledge there is no way to tell if it is the eligard or radiation that is lowering the PSA. Initially I believe it is a good bet that the eligard is the most effective as it can take up to two years for the radiation to effect a nadir of the PSA.
Best to you,
Don