How do you follow/manage patients with metastatic prostate cancer with undetectable PSA and castration-sensitive but active disease on PSMA PET?

Summary: This is a challenging clinical scenario, and one in which I think there is currently a lot of practice variability. In such cases, I would not jump to action immediately, and I would first try to obtain some additional information. This would include repeat PSA for confirmation as well as f...

I’m not sure there is any data to guide us in this situation. Until new data are available, I suggest we adhere to the principle of “first, do no harm” and simply monitor. I obtain PSMA PET periodically (q6 months if no change on PSA q3 months) to evaluate for progression. If there is progression on...

If no disease is seen on conventional imaging, then follow up. If disease is seen, consider biopsy and treat accordingly.

The sensitivity of PSMA PET is low at PSA levels below 0.2 ng/mL. Thus, a positive signal in the setting of an undetectable PSA raises suspicion for a false positive. Also, does an undetectable PSA even warrant a change in care? Probably not.