What are the chances that this is just a PSA bounce?

Hi Brian. I did have a PSMA pet scan before treatment that showed no spred. My gleason score was 3 + 4 but my Decipher was .95. That's when we did the PSMA scan and a decision was made against ADT. It's a bit early for a bounce but I'm hoping for the best.

My biopsy report stated approx 10% 4 so I guess it would be 90% 3. It also stated 70% of the tumor is cancer. I'm not sure what that means. 14 cores were taken and only one showed the cancer. I had 28 imrt sessions and I did have Barrigel and 3 gold markers installed.

Just like with most every other test/scan for prostate cancer - PSA, MRI (PIRADS), biopsy (Gleason), Decipher (decipher score), etc. - a PSMA PET scan always results in a “SUVmax” score, which indicates the aggressiveness of every instance of tracer binding activity they see.

You mentioned that they noted “tracer binding activity in both central lobes of prostate.” They should have then indicated SUVmax scores for both of those. (If not, you should ask what those SUVmax scores of tracer binding activity were.)

Here’s a (very lengthy) explanation of how they use the SUVmax scores to determine cancer location and aggressiveness:

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 as 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).

“SUV” stands for “standard uptake value” and is a measure of radiotracer uptake that indicates how high grade the cancer is. The higher the SUVmax, the more advanced the cancer.

They use the PSMA SUVmax values of your blood (the lowest level), liver (the medium level), and parotid or the lacrimal glands (the highest level) of SUVmax tracer binding expression for comparison.

If a suspicious area (lesion) is expressing PSMA, 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 lacrimal/parotid glands, then it’s likely moderate-grade prostate cancer;

> a PSMA SUV score greater than parotid glands, then it’s likely high-grade prostate cancer;

That PSMA PET information - in addition to PSA, MRI, biopsy, decipher, etc. information - helps guide them in developing the appropriate treatment for your specific disease.

As always, discuss all this with your doctor when you get your SUVmax scores from them for your PSMA PET scan report.

Hi Brian. I'm still trying to touch base with my doctor but I did find the note SUV LO: 0.00 SUV HI : 5.00 below one of my PET images.

Keep checking PSA and look for a trend.

Did you have a PSMA PET scan prior to treatments? Did you have a biomarker (genomic) test?

PSA is expected to be below 0.50 following standard radiation treatments (and if ADT was used, after ADT was out of the system). You should ask your RO if the first PSA of 0.9 was normal and expected.

As for PSA bounce, that’s common following SBRT and brachytherapy (where there is an intense radiation dose); it’s less common for standard treatments of IMRT and proton. Also, PSA bounce is said to occur at 12 - 18 months out (and as far out as 2 - 3 years), and not usually so soon after treatments.

Watch this closely with another PSA test. (Since this is regarding radiation, I’d listen to my RO.)

@brianjarvis I was on Orgovyx starting March 26 and had my SBRT treatment in mid-April 2025. Three months post-SBRT my PSA ws 0.36; six months post-radiation and at two weeks off Orgovyx my PSA was 0.22; at 3-1/2 months off Orgovyx my PSA bounced back to 0.98. My scheduled consultation with the RO is at the end of January. Should I ask if that bounce is so soon based on your comment that "PSA bounce is said to occur at 12 - 18 months out (and as far out as 2 - 3 years) ..."? When I last saw my RO, she said that a rise in PSA will be normal if it correlates (can be explained by) a corresponding rise in my T level. My libido and erection is back to pre-ADT; I don't have a pre-treatment T baseline number, so can't say if T is back as well.

@vircet You can find many PCRI videos (w/Dr. Scholz, MD) on YouTube talking about this topic - what to expect with PSA following each type of radiation treatments - EBRT (SBRT, IMRT, Proton) and internal radiation (brachytherapy: HDR/LDR), and what PSA bounce is all about.
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At each of your PSA tests, it’s important to know what your testosterone levels were.
> At 3 months post-SBRT (PSA of 0.36); were you still on Orgovyx?
> At 6 months post-SBRT (PSA of 0.22) & 2 weeks off Orgovyx, how high had your testosterone levels risen?
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Typically, ADT hormone therapy will push your PSA to nearly undetectable while it’s in your system and then PSA will begin to increase as the ADT wears off. (My PSA remained at 0.008 ng/mL the entire time the ADT (Eligard) was in my system. Once the Eligard wore off, we measured my PSA at 0.198 ng/mL (as you can see in my attached PSA tracking chart). That became my nadir.)

At just 3-1/2 months off Orgovyx (PSA at 0.98), that’s too soon to for a PSA “bounce.” With Orgovyx out of your system, PSA following SBRT should remain very low (“nadir”), but begin to stabilize near your “new normal” PSA levels.

(If it were me, at that next consultation I’d request another PSA (& testosterone) test just to see if PSA is still trending up (or going down). If it’s still trending up, I’d request a PSMA PET scan to get a better view of what might be going on.)

You mentioned, “When I last saw my RO, she said that a rise in PSA will be normal if it correlates (can be explained by) a corresponding rise in my T level.” Yes, that’s true - a slight rise in PSA is normal with a rise in T level. But, that rise should optimally be capped at about 0.2 ng/mL and will be your “nadir.” Then, over time, your PSA may eventuality rise a little more and settle into a range that will be your new normal. (My “new normal” PSA is between 0.35-0.55; if it begins trending well above that range, we’ve already agreed that we’ll start looking into it.)

@brianjarvis Thanks Brian. I will watch the PCRI/Dr Scholz' videos.

Hi Brian. I did have a PSMA pet scan before treatment that showed no spred. My gleason score was 3 + 4 but my Decipher was .95. That's when we did the PSMA scan and a decision was made against ADT. It's a bit early for a bounce but I'm hoping for the best.