Could be other factors influencing factors from biopsy, high PSA. My understanding is risk. Although my PET was negative for the lymph nodes, he still removed my left side obturator nodes to be double checked. I believe it may have been 10. I turned out to be a Gleason 7 4+3. I asked him about the removal prior to surgery and my concern with lymphedema in the legs. He said it was not a concern as the obturator nodes are specifically tied to the prostate.