Which scans are suitable for recurrent PCa with very low PSA

[traveller64]

I had surgery in 2011 and adjuvant IMRT to prostate bed in 2012. Pt3b, Gleason 8 (4+4) with tertiary 5. Psa recurrence 5 years ago, PSA rose from nadir 0.003 to 0.8. Treatment with Casodex since recurrence. Current regimen 50 mg / day.

PSA gradually went down from 0.18 at the beginning of 2019 to 0.05 recently.

My question is : what scans are suitable in my situation? I had a Ga68 PSMA PET/CT two years ago which did not show any mets. Does it make sense to have a PSMA PET/CT at very low PSA? Or FDG PET/CT? Or just don't have any scans and wait until PSA rises?

Thanks

[GP24]

You will probably see nothing with a PSMA PET/CT. You could stop Casodex for six months and let the PSA value rise to 1.0 ng/ml and higher and do a PSMA PET/CT then. You only need this if you want to radiate the mets. No real need to do it at 0.05 ng/ml but on the other hand, nobody can prove this will be wrong.

[Tall_Allen]

Nothing should show up on any known PET scan, which is a good thing.

[traveller64 in reply to Tall_Allen]

Allen, how can we know if the cancer is progressing but not producing much PSA?

[Tall_Allen in reply to traveller64]

That is very rare. You can easily tell from an IHC anaysis of a biopsy of a met. Also, you can detect progression on an MRI.

[traveller64 in reply to Tall_Allen]

MRI? My cancer is systemic? So are you talking about whole body MRI?

[Tall_Allen in reply to traveller64]

No. I was speaking generally. For men with known mets, their size can be tracked with an MRI. If they get larger, it indicates progression.