A 2nd opinion can be worthwhile.
It partly depends on whether radiation has been selected as treatment of choice.
A medical onclogist expert in prostate cancer can provide an objective view to balance that of the urologist or radiation oncologist, and give information on various treatment options, side effects etc.
You could obtain updated information on medical oncologists A Ferrari Mt Sinai Hospital, D Petrylak Columbia University, D Trump Roswell Park.