PSA low: What should I expect with upcoming CT & bone scans?

The bone scan can find things that the PSMA pet scan can’t, Since it’s not dependent on finding PSMA. With your low PSA you probably don’t have any bone metastasis. If you are done with ADT and Zytiga And your PSA has stayed down, That’s even more positive.

While studies did show that even though people are on the drugs and stay undetectable they can get metastasis. When I stopped Zytiga after 2 1/2 years, I did have a metastasis on my spine. Had to have it zapped with SBRT. I never stayed undetectable while on Zytiga however. My PSA was only undetectable for one month in that 2 1/2 years I was on it. It would go from .2 to .7 changing every month. Your .02 sounds promising, unlikely to be something found.

I have learned that PSMA scans go for roughly US$ 1,500 outside the US. Even including airfare and hotel that is much cheaper than what you would need to pay in the US.

PSA is a very strong, specific indicator. There are a few isolated cases in the literature of prostate cancer advancing with PSA < 0.1 or 0.2 on the regular-sensitivity test, but none that I've found so far with PSA < 0.01 or 0.02 on the ultrasensitive test. Even neuro-endocrine prostate cancer expresses a *little* PSA.

A warning, though: while they don't throw up as many false positives as PSMA-PET, MRIs, bone scans, and CT+contrast can light up for things that *aren't* cancer, like a bruised rib healing itself, or bone remodelling around an old spinal injury. Sometimes radiologists will decided to be better safe than sorry, and write that a lucency is "concerning for (new) cancer."

If that happens, don't panic. They did that to me last fall after an MRI. The oncologist told me it was almost impossible that it was cancer with my undetectable PSA and stable bloodwork (especially ALP), but the "c" word was still there, nagging at me, until a follow-up MRI last month concluded that it was just benign bone remodelling around my spinal surgery site.

Best of luck!

@northoftheborder thanks North! I trust you are enjoying being a grandfather now. I hope to experience that someday as well.

@jeffmarc Thanks Jeff! Did the SBRT clean out the spine met that you had so that it was no longer visible on scans?

@johndavis60
My PSA dropped from .2 to undetectable the month after the radiation. At that point there was no way I could have a PSMA PET scan to see if it was gone, PSA too low, but it sure appears to be. By now it would’ve done damage to my legs if it had not been removed.

@topf
I know a guy that went to Austria in order to get an Actinium PSMA pet scan. Price was definitely much more reasonable than here, and it was not even available here yet.