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← Return to first PSA result post salvage RT — 0.086
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first PSA result post salvage RT — 0.086
Prostate Cancer | Last Active: Feb 15 6:22pm | Replies (9)Comment receiving replies
Here’s what they do with that SUVmax of 13.3.
As it turns out, PSMA (prostate specific membrane antigen) is not really “prostate specific.” There are other organs, tissues, and fluids that naturally express PSMA (without being cancerous) and will show up as physiologic tracer uptake on a PSMA PET scan - particularly in the lacrimal (tear) and parotid (salivary) glands, blood, liver, spleen, pancreas, ganglia, and more, as well as the kidneys, ureters and the bladder (as the body tries to quickly excrete the radioligand that was injected).
So, they use for comparison the PSMA SUVmax values of your blood (as the lowest level), liver (as the medium level), and parotid or lacrimal glands (as the highest level) of SUVmax expression.
If your suspicious area is expressing PSMA (yours is 13.3), and it has:
> a PSMA SUV score less than blood, then it’s not likely cancer, but instead just normal, background PSMA cellular expression;
> a PSMA SUV score greater than blood, but lower than liver, then it’s likely low-grade prostate cancer;
> a PSMA SUV score greater than liver, but lower than the lacrimal/parotid glands, then it’s likely moderate-grade prostate cancer;
> a PSMA SUV score greater than the parotid/lacrimal glands, then it’s likely high-grade prostate cancer;
Where does your 13.3 SUVmax fall on that blood-liver-parotid(or lacrimal) SUVmax range?
As always, discuss all this with your doctor.
Replies to "Here’s what they do with that SUVmax of 13.3. As it turns out, PSMA (prostate specific..."
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@brianjarvis
Brian, Many thanks for this information. Given the discrepancy between my PSA and SUVmax, I’ve suspected that there is something being missed in reading the tea leaves of the PSMA PET data. Perhaps this is it. Neither the radiologist who issued the report, nor my urologist mentioned anything about comparing against SUVs of different organs and blood. I will certainly bring this up with my RO and urologist, both of whom I will see in the next couple of weeks.
Do you have any references for these comparisons—journal articles, conference presentations, etc? Would be useful to share those with my docs.
I doubt that the nodule is residual prostate tissue. I had regular DREs following my RARP, as well as PSA tests. In the ninth year after my RARP, my urologist first detected a lump during a DRE, but my PSA was still undetectable (< 0.1) at the time, so there was no further action. It was a year later (June 2025) when my PSA rose to 0.11 that all the alarm bells started going off. I suspect that the recurrence is low grade cancer, but it sure would be good to confirm/correct that hunch with some actual data.