PSMA PET-CT Ga68 Scan results

[KeyboardGuy]

Profile recap: family history of PCa; RALP 5/18/09; post-surgery pathology Gleason 3+3; no evidence of PCa extracapsular or in pelvic lymph nodes. Post-surgery PSA undetectible until 2013, then reached 0.20 in 2017. Most recent PSA 0.56 in January 2023.

Scan was performed on 3/9/23 by Department of Radiology at Columbia University Medical Center/NewYork-Presbyterian Hospital, New York City. Here are the report highlights:

1. No convincing evidence of distant PSMA-avid metastases.

2. Head/Neck: There is no pathologically enlarged or PSMA-avid lymph node.

3. Chest: Mediastinum, hila and lymph nodes: There is no pathologically enlarged or PSMA-avid lymph node.

4. Abdomen: There is no pathologically enlarged or PSMA-avid lymph node.

5. Pelvis:

a. Lymph nodes: There is no pathologically enlarged or PSMA-avid lymph node.

b. Soft tissue: Status post radical prostatectomy. There is a 0.9 cm focus of intense PSMA uptake in the prostate bed, adjacent to the left posteroinferior bladder wall, corresponding to an ill-defined soft tissue nodule on CT (SUV max 40.5, average Hounsfield units 50, 4:81, 3:47).

My PSA has been relatively steady for the past year:

11/17/21 - 0.51

03/07/22 - 0.53

06/14/22 - 0.44 (not a typo - point forty-four)

10/08/22 - 0.54

01/17/23 -0.56

My doubling time is anywhere from 2 to 10 years based on which data points are used in the calculations.

Under the circumstances, I have several questions:

1. Is it possible that the rise in PSA is caused by benign residual prostatic tissue?

2. Is follow-on treatment necessary at this time (or ever)?

3. My medical oncologist has been suggesting that I participate in his clinical trial ( clinicaltrials.gov/ct2/show... ). Is this worthwhile or would this be over-treatment in my case, and would there be any downside?

[Tall_Allen]

1. No. Benign residual prostate tissue does not generate serum PSA.

2. Maybe not. Can you get a Decipher score? Read this:

prostatecancer.news/2021/10...

3. Interesting trial! Maybe decide after you get your Decipher score.

[KeyboardGuy in reply to Tall_Allen]

Maybe I don't understand, but how do I get a Decipher score if there is no specimen to biopsy?

[Tall_Allen in reply to KeyboardGuy]

They have the whole prostate.

[KeyboardGuy in reply to Tall_Allen]

So in other words, I cannot get a Decipher score.

[Tall_Allen in reply to KeyboardGuy]

Sorry - I did not look at the date of your prostatectomy. You are right. You will have to make decision based on your very slow rate of progression.

[KeyboardGuy in reply to Tall_Allen]

Thank you, T.A. The report seems to indicate that all of the PSA is located near the base of the bladder. This is why I was asking about benign tissue, as previous studies have shown that any benign prostatic tissue usually appears at either the apex or the base of the bladder, see ncbi.nlm.nih.gov/pmc/articl..., and some studies have suggested that this benign prostatic tissue might be the source of post-surgery PSA recurrence, see pubmed.ncbi.nlm.nih.gov/110....

I understand that the studies have concluded that benign tissue is probably not the cause of rising PSA, but the way the studies are worded leads me to think that it is possible in rare cases. Thus if I am one of those rare cases, it's a possibility that I would want to pursue.

It is my understanding that the state-of-the-art imaging technology combines PET, CT and MRI, which can theoretically provide a non-invasive visual anlaysis of cells to determine the level of cancer-aggressiveness. If so, I'm thinking that I might be able to delay making a treatment decision until this technology is more readily available.

Alternatively, if there is no downside to participating in my MO's clinical trial, then perhaps I should just go along with it. Either way, I would continue to monitor my PSA going forward.

[Tall_Allen in reply to KeyboardGuy]

How do you propose PSA gets into the serum, if it is benign? I think it is impossible.

goldjournal.net/article/S00...

auajournals.org/doi/10.1097...

But given its very slow growth it is not aggressive, and the clinical trial may be a good way to go.

[KeyboardGuy in reply to Tall_Allen]

It would be the same way that PSA goes up when you have BPH.

[Tall_Allen in reply to KeyboardGuy]

The tissue would have to have a corrupted blood supply too. It's very farfetched.

[tango65]

Is it possible to get a biopsy of the node?

[Justfor_]

There is the Abodart test, but you have to take it for at least 6 months. If, by then, your PSA halves or drops somewhere near it, than it is most probably originating from benign tissue. Cancerous cells will also be somewhat affected by Avodart but not to such an extend.