PSMA shows nothing. Good news or non-news?

[Jimh1946]

Past history is in my profile. My PSA went from undetectable in January 22 gradually to 1.7 in June. Had a six month Eligard shot 6/15, and a PSMA PET scan 7/18. I just read the report. It shows no activity anywhere. I'm a bit confused; is the ADT masking something or should I simply be grateful (My first choice)? And should I ask to add Zytiga now or wait until Eligard failure?

[Tall_Allen]

There's some evidence that hitting a non-metastatic rapid PSADT with 8 months of Zytiga may slow it down:

ejcancer.com/article/S0959-...

[tango65]

Having had a BCR with a regional lymph node, treatment with radiation plus 2 years ADT plus abiraterone should could be considered based in the Stampede study.

urotoday.com/conference-hig...

[NotDFL]

Some prostate cancers don't express (much) PSMA. If that's the case, a PSMA scan won't be helpful.

[maggiedrum in reply to NotDFL]

My understanding is that PSMA is a chemical that carries a detectable radioisotope. It binds to the cell wall of a PC cell. The cell does not have PSMA itself. It does have external cell wall proteins that the PSMA clamps on to.

[NotDFL in reply to maggiedrum]

That's not correct. Here is a link (from academia) with details

radiology.ucsf.edu/psma-pet...

[maggiedrum in reply to NotDFL]

I stand corrected NotDFL. Thank you for pointing that out. I think I misled myself seeing the tracer having PSMA in the name.

[maggiedrum]

A negative PSMA PET scan is good news in and of itself. It is pretty sensitive and would show if you had any PC anywhere else in your bod.

[chips1942]

It is possible that the Eligard shot took your PSA into a range where the PSMA scan has only marginal ability to detect cancer. Or you may be one of the 20% of men who don’t have enough PSMA to make the test a reliable indicator of your cancer.

[savanna1A]

I had 2 PSMA PET Scan done, Nov.2021 and June.2022, shown nothing but PSA going up slowing, PSADT 7-8 months...worried or not!. No ADT yet. last PSA 1.28

[jazj]

Better to have a negative scan than a positive scan ADT or no ADT.

"The sensitivity rates of PSMA PET/CT according to PSA levels are 55-60% (0.2-0.5 ng/mL), 72-75% (0.5-1.0 ng/mL), 93% (1.0-2.0 ng/mL) and 97% (≥2.0 ng/mL)."

ncbi.nlm.nih.gov/pmc/articl...

As I understand it, ADT puts the cancer into temporary remission until it switches over to no longer relying on Testosterone/DHT to fuel its growth. So yes the cancer is still there but the PSMA scan is reflecting that the ADT actually reduced the amount of cancer, it's not just masking the PSA in my opinion. Not sure how long your Oncologist plans to keep you on the Eligard but studies have shown there's no much difference in the long-term outcome if you do relatively shorter-term ADT taking breaks as opposed to long-term 2+ years in exchange for better quality of life during the ADT vacations.