Flare in Prostate-specific Membrane Antigen PET Tracer Uptake with Initiation of Androgen Pathway Blockade in Metastatic Prostate Cancer.

[tango65]

The study confirms what it has been posted here by GP24 and others that ADT and Enzalutamide may increase the tracer uptake by the cancer cells. The uptake flare in this situation is not an indication of disease progression. Prospective study with few patients and short follow up.

ncbi.nlm.nih.gov/pubmed/311...

[Schwah]

Thanks for this post. But I’m a lithe confused. Does this study imply that someone on ADT who does the psma test, may show an advancement of their disease even if it is not advancing ? Would this continue over time or supposedly occur only during the early weeks and months of adt? If it continues wouldn’t it render the psma test unreliable ?

Thx

Schwah

[tango65 in reply to Schwah]

I think it applies to patients who had a Ga 68 PSMA positive, then start ADT plus/or an anti androgen (my situation in 2016) and a subsequent Ga 68 PSMA could show higher SUVs in the metastases. I believe the findings in the study are important for patients considering Lu 177 PSMA or Ac 225 treatment. Pretreatment with ADT and or an anti-androgen could increase the expression of PSMA and could make the treatments more effective.

[GP24 in reply to tango65]

I agree and cannot add much. When you do Lu177 therapy and the PSMA expression is increased, more of the injected ligands will bind to the tumor cells and not to healthy cells. This may cause fewer side effects of the Lu177 treatment.

If you increase the PSMA expression before a PSMA PET/CT, you will see more metastases. This is ok before a Lu177 treatment. But if you want to be classified as oligometastatic and plan to zap the mets with Cyberknife, you better do not get more than five mets or they will refuse to treat you. In that case you better do not increase the PSMA expression. The teeny tiny mets do not need to be zapped anyway, zap those some other time.

[Hidden]

Here you can see the graphs for better understanding:

sci-hub.tw/10.1016/j.euo.20...