Would you recommend biopsy of a bone met noted on PSMA PET after definitive prostate radiation?   

There is no simple answer to this. The following are some relevant considerations: What was the original risk category? What was the Gleason score? What was the pre-treatment workup? Was there anything noted there previously? Was or is the patient on ADT? Pre-treatment and current PSA values? ...

I presume that the patient was treated for localized prostate cancer. Then had some appropriate interval of decrease in PSA. And now has developed biochemical recurrence (per Phoenix definition) which prompted a PSMA PET/CT. For the basis of argument, I will assume that there is one location that is...