I asked my RO that once. I looked him right in the eye and said "If your sitting right here in my shoes, what would you do?"
He gave that a little more thought.

I found my cancer be being insistent with my doctors (whom I liked and respected) that I wanted to know what it was. I did not want to take a wait and see approach and I did not want to try going on anti-virals for a few weeks to see is they worked.

I am amazed you cannot get a biopsy for peace of mind.