EMPIRE 1 results published

[ramsesthenice]

This is my big concern with all the molecular imaging data is that I am not aware of any series doing a thorough evaluation of positive predictive value and radiologic/pathologic correlation study before just treating it as gospel.

For example, the false positive rate of PET in vulvar cancer in inguinal LNs (25% of PET avid inguinal LNs will actually be negative on lymph node dissection). What percentage of F18 (or PSMA) PET positive inguinal LNs in prostate cancer are actually negative on path evaluation? What percentage of F18/PSMA PET positive in the ribs, the spine, the soft tissues, whatever, are false positives on path evaluation?

I can’t give you a number but in my experience clinical context matters. Someone with a biochemical recurrence 3 years after surgery and a modest PSA doubling time almost certainly doesn’t have multi focal macroscopic bone Mets. If something doesn’t make sense clinically I do biopsy before drastically changing therapy.

All that said, I got a shocker a couple months back. Guy had a biochemical relapse with a PSA of 1 and PET showed an RP node and RUL nodule that was hot. Something like 20% of NSCLCs express PSMA and I was sure he had a lung primary but alas, biopsy showed prostate cancer. SBRT to both with complete biochemical response as of last week. He will progress eventually but he’s happy for now.

I would say the specificity for pelvic and RP nodes is probably pretty good. I do a fair bit of focal salvage and in those setting I can’t recall a single time I didn’t get a good (at least initial) biochemical response in the absence of concurrent progression.

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[Palex80]

Here's a case of a suspicious PSMA-positive lesion in the bone in a patient with a rising PSA post prostatectomy. CT also showed a bit of sclerosis in the bone matching the location of that PSMA-avidity. Bone biopsy came back negative. No other lesions on PSMA-PET-CT. We treated only the prostatic fossa, the PSA dropped below detection levels.

 

[evilbooyaa]

Here's a case of a suspicious PSMA-positive lesion in the bone in a patient with a rising PSA post prostatectomy. CT also showed a bit of sclerosis in the bone matching the location of that PSMA-avidity. Bone biopsy came back negative. No other lesions on PSMA-PET-CT. We treated only the prostatic fossa, the PSA dropped below detection levels.
View attachment 336964

I know at least 2 MDTs that would've advocated for SBRT of the iliac lesion without biopsy. I suppose that's my question and the fact that this is a data-free space (and the part that people don't seem to have any interest in studying). If anyone is aware of presented/published research in this space, please educate me!

 

[Palex80]

I know at least 2 MDTs that would've advocated for SBRT of the iliac lesion without biopsy. I suppose that's my question and the fact that this is a data-free space (and the part that people don't seem to have any interest in studying). If anyone is aware of presented/published research in this space, please educate me!

Excellent, evilboy, this is precisely the point!

But then the PSA would then not drop.
And you know what would then (most likely) happen?

The urologist/oncologist would conclude that the PSMA-avid lesion was simply "the tip of the iceberg" and the patient is not oligometastatic. Perhaps another scan would take place (most probably a CT, since there may be issues in getting another PSMA-PET-CT reimbursed within 3 months), it would probably come back negative and the patient would then be put on life-long ADT (perhaps even with Abi or Enza!).

Isn't it wonderful, how superior diagnostics (PSMA-PET-CT) just ruined this patient's chance of getting cured with salvage RT for his local recurrent tumor in the prostatic fossa?

 

[Ray D. Ayshun]

I'm joking here, but was biopsying that thing more or less toxic than sbrting it?