You say ..."His post-prostatectomy persistent PSA has dropped from 4.7 to .04..." I just have not seen someone with a persistent PSA of 4.7 after surgery, detectable yes, but one to two decimal places more common.

So, he had surgery...what was his PSA just before surgery, what did the pathology report say, frequency and results of PSA tests since...?

I ask because as I read your post that clinical data is useful in shaping the group's response...

Is he on doublet therapy for a defined time,,12, 18, 24, 36 months, "indefinitely...!?"

Things like PSADT, PSAV, GS, GG, any genomic testing...all factor into treatment decisions.

His response you describe from 4.7 to .04 in five months is a positive indicator treatments working and if it is for defined period, a clinical data point indicating longer PFS and RPFS.

Imaging at .04 may be as doctors like to say about some supplements, just result in expensive urine...!

The decision to image is generally a function of the purpose, why, what do we do with the results, does it change our treatment plan...also, what are the statistical probability it locates anything...pretty darn low at .04!

There is also the insurance coverage issues sometimes and any financial toxicity associated with that.

Knowing the little I do from what you post, what would I do were I he? Remember, I am not your medical team!

Continue treatment for whatever period the original decision was for.

I would not image at that PSA.

I would discuss with his medical team the clinical criteria for coming off treatment at the end, if not before, of an agreed upon defined period.

I am not in the camp for indefinite treatment, fired one urologist who said that's what I should do, there are diverging views on intermittent versus continuous so you, your husband and your medical team are going to have to discuss that. It has worked for me...we have clear criteria for coming off, monitoring while off and what constitutes sufficient clinical data to go back on. My breaks have been almost five years after triplet therapy and 21 months and continuing after doublet. T had recovers in the first 3-6 months which is a factor. There are some whose T does not recovery, age, baseline T, duration and type of agents used in systemic therapy as well as lifestyle all may be factors. Those on this category may not "enjoy" their breaks as much...

If you have not, consider consulting with another radiologist about treating those spots, doesn't hurt. As my radiologist says, get a group of medical specialists together in a room to arrive at a single solution, good luck with that!

As to the duration of systemic therapy, that is a function of the clinical data, GS, GG, PSADT, PSAV, Pathology Report, testing such as Decipher, Genomic...

Kevin