Another visit yesterday with undetectable PSA which is pretty incredible considering where I was in 2017.
Onc, Mayo, says I get my first PSMA in 3 months. With no advancement on MRI’s, CT’s, and bone scans over the last 4 years is there any reason to believe there would be anything on a PSMA?
Hi Survivor1965,
That’s good news. Like you, my PSA remains undetectable following an RP in 2019. I had a PSMA-PET CT scan in 7/21 at the VA in LA as part of a four hundred patient clinical trial. Although my PSA was undetectable, the RO conducting the trial told me that he’d recommend including me as part of the group because he’d discovered patients with undetectable PSAs who had micro-mets that were revealed during PSMA-PET CT scans. At first, I found this information disheartening, but then I concluded that the sooner we know that we’re growing distant micro-mets and can actually find them, the sooner we can tailor our future treatment plans accordingly. There are false positives that occur with PSMA-PET CT scans, but for me, I want to know about whatever is growing wherever it’s growing as soon as possible. So, it’s my opinion whenever you can get a PSMA PET CT scan you should do so. Others may have a different opinion.
Jeff
Thank you, that is very enlightening Peace
If PSA is undetectable, I understand that Pet scan can't pick upnmets. Wait until it goes up?
If you have undetectable PSA, the PSMA scan will be negative. The scan works by detecting PSA on a cell’s surface.
This is false. PSMA and PSA are two different things. PSMA is prostate-specific membrane antigen and is an attribute of the cell. It does not circulate in the bloodstream. PSA is produced by prostate cells and does circulate. A measurable PSA does not mean that you will necessarily have PSMA-avid cells show up on a scan, and an undetectable PSA does not meant that you will not have PSMA-avid cells.
I have had a PSMA PET scan with an undetectable PSA to determine what residual disease I had after treatment. It found several nodes that were PSMA avid.
Thank you very much! I’ve never Jesuit explained this way before, and truthfully I don’t really understand it that well anyway. Many thanks
The detection rate when there is undetectable PSA is very low.
Hoping I’m in that category.
The detection rate with undetectable PSA is very low, usually less than 30 or 20% If I recall correctly.
If your PSA is undetectable and stable and you do not have any symptoms it is my humble opinion that the scan is not indicated.
There are cancer that can progress with low PSA but they usually express very low PSMA and the mets may not be detected by a PSMA PET/CT.
20-30 percent is pretty significant.
That was my thought too. And with my very aggressive disease why not get the scan, especially if my onc recommends.
My mistake, it was not undetectable PSA, it was PSA < 0.2. We do not know how many patients in this group had a PSA less than 0.1.
tango65, can you recall where you saw that 20-30 % figure? I thought the percentage would be smaller.
My mistake, it was not undetectable PSA, it was PSA < 0.2. We do not know how many patients in this group had a PSA less than 0.1.
urotoday.com/recent-abstrac...
Thanks, tango65, this is a most useful study., concerning patients with biochemical failure who had PSMA PET/DT. If it is correct to assume that biochemical failure is defined as a PSA rise, the 11 patients with under 0.2 might all be over 0.1. In that case, 7 out of 11 with such a small PSA rise lit up under PSMA. The lesson I make is that one should have a PSMA scan asap after it rises above 0.1.
Confusingly for me, the sum of the rows below "PSMA positive" is only five, not seven.
I wouldn't do it. There might be some false positives show up that will only worry you. It would be unlikely to be of benefit generally. It is possible that cancer grows in a PSA-free environment but I think it would show up on a CT scan.
Thank you for your input
Try watching this video. youtube.com/watch?v=8fajSFz...
That was so good! Thank you
Good news but agree you can have PSMA expressed without PSA detectable. Probably the reality is for follow-up and initial workup we need both a metabolic based PET/CT such as Mayo's C-11 Choline (which needs to become more available), F-18 Axumin (increasingly falling out of favor) or FDG (at best 20 percent detection of prostate cancer so not usually recommended), as well as a targeted PET/CT such as PSMA and whatever the future holds for additional targets which are being developed and will no doubt be available in Europe before here. My two cents worth.
I’ve probably had 20 C-11 scans over a 7 year period both at Rochester Mayo and Mayo Phx.
Kwon says he sees things on PSMA Pet that do not show on CT or MRI for up to 8 years. So yes, you are likely to see things not showing on prev scans. But seeing is good. You cant fight directly, what you cant see. As we all know, early is usually better with almost everything PCa related.
Best of luck my friend,
Mike
PSMA PET scan 
pSMA scan question 
PSMA scan result
PSMA PET scan
PSMA Pet Scan results 
