Sandg, my biopsy was conducted by my local Urologist. I contacted Mayo and gave my Gleason 4+4 score on the phone and Mayo had my Urologist send the films of the results. I contacted Mayo and not my Urologist. Mayo contacted within a week and agreed to treat me. I was not at Mayo before they accepted me. The next week I met with the oncology radiologist. He then arranged a bone scan and series of MRIs to ensure the cancer was inside the prostrate. The process was extremely fast and thorough.
I was accepted by Mayo in 2018, so not sure if they as quick now, but my guess is you can do it without going to Mayo before they might accept you.