BAT initiated - PSMA/FDG scans negative

Oncologist very surprised, PSA 1.5, either PSMA or FDG scans should detect metastases. Anyone has an explanation? Lots of micrometastases not detected?

Anyway, MO initiated BAT.

[ragnar2020]

Hello SHH696,

I find your situation interesting and slightly similar to my own. I had an RARP in 9/19 and then SRT in 9/22. I have had neither HT nor chemo. I have had two PSMA PET CT scans prior to SRT in 9/22. The more recent PSMA PET CT scan revealed a tiny lesion on my sacrum. The SRT apparently removed it as determined by a 1/9/23 MRI.

But, because MRIs are not as sensitive to tumor growth as is a PSMA PET CT scan and what it may reveal, I'm in a dilemma if I have micro tumor growths sprouting in my body as a result of circulating micro PCa cells that presently defy imaging possibilities. In May '23, I suspect my MO will approve a PSMA PET CT again, and we'll find out what has been growing and where.

Prior to the SRT, my PSA had become elevated to .21. Following the radiation, my PSA is at .14. Not perfect, but lower. Something is growing someplace.

I may need to begin systemic ADT treatment, but because of cardiac issues and osteoporosis, I'm leaning towards beginning ADT with tE2 gel and self-monitoring my lipid, psa, T an E levels with private pay blood testing.

We know that the use of tE2 for ADT is not accepted in America by the attorneys representing the institutions against malpractice lawsuits from those attorneys seeking customers who wish to litigate against deep pocketed medical institutions with malpractice insurance in place. It is a grim world out there for PCa patients who do not fit into the SOC COE mold of care.

[Hidden in reply to ragnar2020]

Did you perform a FDG scan?

[ragnar2020 in reply to Hidden]

Hello SHH696,

I did not. My MO is at Dana Farber, and I had my most recent PSMA PET CT scan there. I had my SRT at UPenn's Robert's Proton Treatment facility in Philly, and they did the follow-up MRI after the radiation was completed. No one suggested the FDG scan at either location. I went to the HartfordHealthcare Cancer Institute for the last MRI in 1/23, and no one there suggested the FDG scan either. At Hartford, I was seeking entry into the LU-177 RCT and the first requirement of entry was visible lesions from an MRI. My results with nothing present on their MRI booted me from consideration for the LU-177 RCT. I'll ask my Dana Farber MO about the FDG scan. I'll let you know the results of my inquiry. Thanks for pointing this out.

JPD

[Hidden in reply to ragnar2020]

This is why we performed a FDG scan,:

PSMA and FDG screening for eligbility for luPSMA treatment, very instructive

[GP24]

I had to wait for the PSA value to rise to 3.0 to get the PSMA PET/CT to show the mets.

[Hidden in reply to GP24]

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).

My MO recommends PSMA petscan if the PSA is above1, makes sense.

[GP24 in reply to Hidden]

Usually the study by Fendler is used to estimate the sensitivity rates of a PSMA PET/CT. According to that you have a 20% chance that nothing is detected at a PSA value of 1.5. I just reported what happened to me.

PSA values and successful PSMA PET/CTs by Fendler

[Hidden]

PSA rose to 7.3 a month ago, MO rechallenged with Enza. After 14 days PSA dropped to 0.5.