This new scan should see what is producing the PSA and maybe it can be irradicated.
This seems to be a common misunderstanding about
metastatic spread. I have likened treating individual metastases to picking mushrooms in a forest. The fungus extends throughout the soil and reaches down to the roots of trees. It sends up "fruits" - the mushrooms -periodically, but picking the mushrooms has no effect on the fungus; unless you sterilize the soil with a fungicide, the mushrooms will keep on coming. This is what "systemic" means - the metastases you can't see are everywhere. You can only see some of the larger ones. There is no evidence that picking them off has any effect on the course of the disease. When they tried to do that, more metastases kept springing up like mushrooms in distant places in almost all the men. Your best hope is to treat what you can't see as well as what you can see.
So is there anyharm
in waiting for PSA to rise high enough so that metastases can be detected, and then picking them off? Yes, because we learned this year that delaying hormone therapy can double the death rate. There is no harm in treating metastases if you are taking systemic therapy (i.e., hormone therapy) already, but there is no evidence yet that it will extend survival.