Cancer that doesn't express PSMA

[Trasmc]

Hello everyone - thanks in advance for any thoughts or opinions!

Here's the abbreviated version of my story:

My father was diagnosed at 51 and died at 52 of metastatic prostate cancer (think his PSA at time of diagnosis was in the 40s, but cannot remember for sure).

I've been diligent with PSA and DRE since I was 25 (yes probably way early for the testing, but I at least have a long string of data points). My PSA has never been over 1.45.

In 2019 (was 50 at the time) my PCP found an abnormal DRE and referred me to a Urologist (PSA 1.24 at the time) The urologist thought it was a calcification and did not order any additional testing (assuming due to the low PSA). In retrospect I should have pushed for more testing, but I got an answer I wanted to hear and moved on. I had annual appointments with this urologist for 4 years until he retired and referred me to another MD in his practice. In November of 2023 the new MD (despite a continued low PSA of 1.23) ordered a MRI due to the abnormal DRE.

In pretty quick timing I found I had - PIRADS 5, biopsy, 6 of 12 cores positive (all left side), Gleason 7 (4+3). PSMA-PET showed no additional spread and "Ill-defined radiotracer uptake within the prostate on early phase imaging without localization of a focal lesion."

RALP at a nearby NCI Treatment Center in January of 2024, pathology showed no spread at all, no sign of cancer in any of the 7 lymph nodes taken. Also several weeks later got my Decipher results (this was ordered before the surgery but I didn't get the results until later) with a disappointing .99. Surgeon (different urologist than the one that did the biopsy) suggested follow up with ultra-sensitive PSA testing every 6 months.

Because of the high Decipher score I followed up with an oncologist to see if there was anything else I could or should be doing to minimize the chances of recurrence. The oncologist seemed a bit perplexed - I had what was likely high-risk cancer for 4 years without any EPE or evidence of spread on the PSMA. He seemed relieved when he read the PSMA comment listed above about the "...radiotracer uptake within the prostate..." as he believed that this suggested my cancer expressed PSMA and therefore it was a useful tool. He suggested ultra-sensitive PSA every 4 months and repeat imaging at the end of this year. I've had 2 follow-up PSA tests and both have been undetectable.

I had another follow-up with the urologist who did the surgery this week, and he believed that I have a cancer that does not express PSA, and therefore a PSMA might not be as valuable. He suggested a repeat "regular cancer" PET scan instead of a repeat PSMA. He also thought that since the PSA tests were cheap and relatively non-invasive there was some value to continuing them.

So I'm honestly confused - what type of surveillance should I expect moving forward, and should my next scan be "regular cancer" or PSMA? Any other thoughts? Sorry for the long post and thanks again for any opinions!

[Tall_Allen]

Very wise to order an FDG PET in your case. Most common PSMA PETs are excreted quickly from the kidneys so it is common to see the indicator in and around the prostate even when there is no PSMA-avid cancer there. Let us know what the new PET scan shows.

[Trasmc in reply to Tall_Allen]

Thank you and I definitely will. Is the FDG PET what the urologist was likely referring to when he described a "regular cancer" PET scan? He mentioned that it keyed in on high metabolic areas (or something like that) but I'm not familiar with the different types of PET scans. Thanks again!

[Tall_Allen in reply to Trasmc]

Yes, that's the one. Most cancers, except ordinary prostate cancer, metabolize glucose, which is the G in FDG.

[Trasmc in reply to Tall_Allen]

Got it - thanks!

[dhccpa in reply to Tall_Allen]

Damn! That may explain why my prostate was practically a light bulb inside the prostate while no significant uptake was detected outside prostate, both contradicting all previous scans.

[dhccpa in reply to Tall_Allen]

A followup to this comment, which I interpreted as causing the prostate to "light up" with higher uptake (far higher) than, say, Axumin scan or a PET Bone Scan. My first PSMA in July showed SUV of 24.7 in the prostate, compared to an SUV in prostate of Max of 4.5 in all previous non-PSMA PETs.

Did I interpret your comment correctly? If so, have you done a "write-up" on it that I can show my doctors. They seem to be unaware that the PSMA is not the gold standard in any and all prostate cancer situations, and I'm trying to educate them. I searched around but didn't quite find details on this question. Thanks very much.

[Tall_Allen in reply to dhccpa]

Your doctor may not want to read one of my articles-- they are meant for patients. This is explains the various PET scans:

prostatecancer.news/2016/12...

You can be confident that the prostate SUVmax of 24.7 is indeed cancer. Don't forget that all PET scans are given with full-body CT scans, and the radiologist searches the CT for growths that may not show up on a PET scan. If he hasn't flagged any for you, and none showed up on a PSMA PET, it is unlikely they are big enough to show up on another PET scan.

[dhccpa in reply to Tall_Allen]

Thanks

[Seasid in reply to dhccpa]

If you have on the psma pet scan a cancer in your prostate of SUV Max of 25 than it is a substantial cancer.

If this cancer in your prostate is not treated and stays that way it could eventually metastase out from your prostate.

Unfortunately that is the risk what we are facing as we all know.

[dhccpa in reply to Seasid]

It is being treated but now we may radiate it after all these years.

[Seasid in reply to dhccpa]

Good luck and you could ask for second opinion online from a Dana Farber cancer institute radiation oncologists or you could even go there in person whatever you feel more comfortable and appropriate for you. I said to you that you could even arrange a radiation here in Sydney, Darlinghurst if you contact Genesis Cancer Care.

[j-o-h-n]

Greeting Trasmc,

First of all my condolences regarding your Father's passing at his young age of 51 when you were in your twenties.

At 55 you have a full lifetime ahead of you, and with all the new meds and etc. I would predict you'll make it to your 90's. You have come to the right place for information and also comradery. If possible update your bio section for your benefit and for ours. Keep plugging away and remember to live (and to laugh). God Bless....

Good Luck, Good Health and Good Humor.

j-o-h-n

[Trasmc in reply to j-o-h-n]

Thank you j-o-h-n, I really appreciate it!

[dhccpa]

Great question. I finally had my first PSMA scan and it contradicted every single scan I've had over almost six years (many types), meaning PSMA showed no uptake outside prostate. But doctors seem to think it overrules everything that came before.

[lowT163]

psa for me was similar. Felt a nodule at 1.5 and was told no cancer. 2 years later it’s 4.25 out of the prostate. So DRE and MRI with PSMA scan often if you feel a tumor.

[kiteND]

I am one of those with consistent PSA readings of undetectable but my PSMA scans show tumors. And I personally know other men in the same situation. Perhaps theoretically, there must be some PSA for a PSMA scan to work, but the idea that an undectable PSA will make a PSMA scan worthless is not true.

[ritchiek in reply to kiteND]

The PSMA PET CT scan detects PSMA, not PSA. They are different.

[ritchiek in reply to ritchiek]

PSMA is a prostate-specific membrane antigen, as opposed to a prostate-specific antigen- PSA.

[kiteND in reply to ritchiek]

Thanks for reminding me of that. I knew that, but brain fog must have got in the way. 😆

[Seasid in reply to ritchiek]

You are missing the point of what kiteND said. He said that despite no detectable PSA it is worth having the psma pet scan and if you want you could get any other scan like a nuclear medicine bone scan etc. The problem with the bone scan is that it could detect fauls positives.

[NanoMRI]

As you asked for "Any other thoughts? " Since my third treatment over six yeas ago I have been relentless in my surveillance of this beast with bi-monthly uPSA testing, looking for <0.010 post RP as best indicator (not IMO misleading term 'undetectable'), annual imaging with a variety of methods/contrast agents and liquid blood biopsy testing.

As I share, nearly seven years ago I had successful imaging with Ferrotran nanoparticle MRI whilst the concurrent Ga68 PSMA PET was clear. My reality - the PSMA missed all six of my cancerous pelvic lymph nodes found during salvage pelvic lymph node surgery. As the Ferrotran is only in Europe it is most unlikely you will hear of it in US, nor see it in any US comparison write-ups.

IMO the key is to try multiple imaging methods to see if any will identify your possible sites. Thing is, insurances resist and some docs (being kind) are reluctant to seek out multiple imaging methods and contrast agents as they may have to work hard to justify with insurance providers and often have contracts/financial incentives for what they recommended (and not the other methods).

As for your seven nodes being clear, all to often it seems this beast gets out and travels without leaving a trace. The reason I chose to not give this beast time and obscurity. And just this week I face metastatic liver melanoma despite my two melanomas showing no indication of spread at the time of surgery.

Few docs seem to recommend/handle liquid blood biopsy testing - again it seems reluctance by insurance providers and lack of contracts/financial incentives. I hope this helps. All the best!