pSMA scan question : If you get a pSMA... - Advanced Prostate...

Advanced Prostate Cancer

20,782 members25,888 posts

pSMA scan question

Chris52981 profile image
52 Replies

If you get a pSMA scan and you have prostate cancer that metastasized does it alway express PSMA?

What cases will it not?

Also when psa goes up does that necessarily mean there are new metastasis or can it just means same ones are active again?

Written by
Chris52981 profile image
Chris52981
To view profiles and participate in discussions please or .
Read more about...
52 Replies
Poowater profile image
Poowater

No, to the first question. Getting an FDG scan either shows other metastases, or not. When psa goes up either could be expressing psa.

Tall_Allen profile image
Tall_Allen

It expresses PSMA about 90% of the time, but as it progresses, it may not express PSMA. Also metastases are heterogeneous- some cells express PSMA and some do not even within the same tumor. Also, within the same patient, some metastases may express PSMA and some may not.

"Also when psa goes up does that necessarily mean there are new metastasis or can it just means same ones are active again?" Either.

Chris52981 profile image
Chris52981 in reply to Tall_Allen

so what exactly is the point of the PSMA scan to see what treatments your body may respond too? I'm just a bit confused still on the whole reasoning! Thanks for explaining

Tall_Allen profile image
Tall_Allen in reply to Chris52981

That's why I advocate getting both a PSMA and an FDG PET scan.

fmenninger profile image
fmenninger in reply to Tall_Allen

also, sometimes it’s easier for Mo to call for an fdg pet vs psma pet and having both can provide more info.

dhccpa profile image
dhccpa in reply to Tall_Allen

Great feedback from you on this topic. Is the FDG PET known by another name? I had a PET Bone Scan the first time four years ago, but the report details call it something else besides FDG.

Tall_Allen profile image
Tall_Allen in reply to dhccpa

Sometimes called a glucose PET scan - FDG=FluoDeoxyGlucose. As cancer mutates, it loses PSMA expression and metabolizes glucose, like most other cancers do. Bone PET scans are Sodium Fluoride (NaF18).

dhccpa profile image
dhccpa in reply to Tall_Allen

Thanks. Yes, I believe it was NaF18 that I had back then, so I've never had the FDG scan.

Chris52981 profile image
Chris52981

do you want it to express PSMA or no?

Tall_Allen profile image
Tall_Allen in reply to Chris52981

PSMA targeted therapies (e.g., Pluvicto or some BiTEs) require PSMA avidity in order to be effective.

Chris52981 profile image
Chris52981 in reply to Tall_Allen

is a psa of 1.2 very high you think to show PSMA or Mets

Tall_Allen profile image
Tall_Allen in reply to Chris52981

It should show any PSMA-avid tumors.

lewicki profile image
lewicki in reply to Tall_Allen

Would a PSA of 0.04 PSMA pet show cancer and would an Auximin pet scan be a good choice ?

Tall_Allen profile image
Tall_Allen in reply to lewicki

No- neither is a good choice at such low PSA

lewicki profile image
lewicki in reply to Tall_Allen

Thanks. If you suspect cancer may have mutated would the FDG scan be an option. At what PSA will the PSMA scan work?

Tall_Allen profile image
Tall_Allen in reply to lewicki

No scans before PSA=0.5

lewicki profile image
lewicki in reply to Tall_Allen

Again thanks.

garyjp9 profile image
garyjp9 in reply to Tall_Allen

If your MO is suggesting you stop ADT +ABI at the 2+ year mark because your PSA is undetectable (following an RP, N1 disease, and initial post-surgery PSA of 3.4), is there any value in getting an FDG scan or any other kind of scan (not PSMA) before doing so? Thank you.

Tall_Allen profile image
Tall_Allen in reply to garyjp9

Probably not. Unlikely that you have non-PSMA-avid metastases.

garyjp9 profile image
garyjp9 in reply to Tall_Allen

Thanks, I thought maybe I should ask for a scan before stopping treatment after reading this report on an analysis of ARCHES data by Andrew Armstrong: dailynews.ascopubs.org/do/a... Is this not relevant to the situation I've described here?

Tall_Allen profile image
Tall_Allen in reply to garyjp9

That trial was for men who were metastatic- you're not. I think you had potentially curative adjuvant hormone therapy, no?

garyjp9 profile image
garyjp9 in reply to Tall_Allen

Thank you for responding, TA. My metastases were confined to the pelvic lymph nodes, but I am often confused about how to categorize them in the context of studies like this, as to whether they qualify as "metastases" or not. Yes, I have had surgery, radiation (#39), and ADT+ABI (2+years) since 9/20.

Tall_Allen profile image
Tall_Allen in reply to garyjp9

It's confusing because pelvic lymph nodes (stage N1) technically are metastases, but in trials like ARCHES, STAMPEDE, etc., they use the term "metastatic" only to refer to more distant metastases (stage M1).

garyjp9 profile image
garyjp9 in reply to Tall_Allen

Thanks very much for explaining, TA

lewicki profile image
lewicki in reply to Tall_Allen

Is their any harm doing the scan often or just occasional?

Tall_Allen profile image
Tall_Allen in reply to lewicki

Yes- it's radiation from both the radioindicator and CT- do it only when needed.

Justfor_ profile image
Justfor_ in reply to lewicki

A nomogram predicts a 18% probability for a PSMA positive detection at PSA less than 0.1 and a PSADT of 3 years or more, if memory serves. For PSADT shorter than 3 months it can double up.

Chris52981 profile image
Chris52981 in reply to Tall_Allen

so if there are no pSMA avid tumors will it just show plain Mets too? Also if it doesn't show pSMA avid tumors does that mean it could be nueroendocrine or not necessarily? Thanks again

Tall_Allen profile image
Tall_Allen in reply to Chris52981

No PSMA-avid tumors show up at such low PSA. PSMA PET only shows tumors with PSMA expression. Conventional imaging can sometimes show larger tumors that do not express PSMA. Many tumors do not express PSMA.

Chris52981 profile image
Chris52981 in reply to Tall_Allen

6 months ago he received a CT scan of chest and abdomen and he was on Zytiga - it showed little change in measurable disease- they switched him to xtandi bc his Psa was rising and then he went into adrenaline insufficiency and had to stop xtandi and titrate back up- his psa went down went he went on xtandi then a month later they took him off because of symptoms which turned out from not being on prednisone- now he is back on the four pills since January and his psa went up like I said from .6 to 1.2 in three months ( got in beginning of march) - now he wants to give him the pSMA scan on Wednesday- so i am not sure this is the correct way to go about it? Obviously we listen to dr but I also want to make sure there is not other test we should be asking for as well. He had Axumin in past as well- do you think that sounds like a good plan-?

TeleGuy profile image
TeleGuy in reply to Tall_Allen

Never say "never." Here's a left paraaortic lymph node at SUV=6.1 on a PSMA PET scan while my PSA had been <0.01 for 11 months post Lu177-PSMA treatment. We wanted to see where there might be residual disease after treatment and we found several locations.

PSMA PET scan image
Tall_Allen profile image
Tall_Allen in reply to TeleGuy

How do you know it's a true positive? Was there a CT correlate? SUV max=6.1 probably isn't far enough above background to make a definitive call.

TeleGuy profile image
TeleGuy in reply to Tall_Allen

We did a biopsy of one on the other side of the aorta that wasn't as avid. Adenocarcinoma with neuroendocrine differentiation. Then we radiated the collection of them.

Tall_Allen profile image
Tall_Allen in reply to TeleGuy

You may want to explore some clinical trials:

prostatecancer.news/2016/12...

TeleGuy profile image
TeleGuy in reply to Tall_Allen

Thanks. We're considering the BiTE trials but plan to do a biopsy of what's changed since I did 6 cycles of docetaxel+carboplatin.

in reply to Chris52981

there are therapies that assume/require psma.expression .Those therapies then have a chance of being effective.

tango65 profile image
tango65

Cancer mets which do not express PSMA may be bad news, since neuroendocrine PC expresses little PSA and PSMA and it is practically impossible to control.

The regular adenocarcinoma expresses PSMA and PSA and it is usually easier to control than cancer which does not express PSMA or PSA.

The Vision trial leading to the approval of Lu 177 PSMA treatment did not accept patients with mets having a PSMA expression lower than the liver .

Since the mets are not homogenous with all the cells expressing PSMA, it is necessary to have in the mets enough cells expressing PSMA which can attach to the Lu 177 and irradiate themselves and the non PSMA cells in their proximity. Beta particles can travel a few mm in the tissues.

Chris52981 profile image
Chris52981

thank you everyone! Makes so much more sense!

fmenninger profile image
fmenninger in reply to Chris52981

This is why we should not rely 100% on just psa. As many in this forum have said, we warriors are not fighting psa but rather pca and psa is one of many bio markers and new tools such as psma pet scan should be used when warranted.

Stay strong!

wagscure259 profile image
wagscure259

In my case doubling times of PSA were 3-6 weeks and scans showed rapid lymph node disease progression. After 10 years of treatment with Lupron, bicalutamide and darolutamide when progression was noted I had both a PSMA scan, FDG scan, bone scan, and biopsy of positive lymph node to rule out neuroendocrine PCA ( along with histochemical testing- because at the time of rapid progression my PSA was around 2), still adenocarcinoma and my cancer was NOT PSMA avid but FDG scan reveal extensive retroperitoneal and pelvic side wall lymph node metastasis. Presently being treated with docetaxel with favorable responses after 3 rounds. Best to you.

Gl448 profile image
Gl448 in reply to wagscure259

How did they determine favorable responses after three rounds? PSA levels or something else

I have my 4th round in 2 days and PSA has dropped, but I’m one of those whose cancer doesn’t express (much) PSA.

wagscure259 profile image
wagscure259 in reply to Gl448

Primarily from CT scans of chest, abdomen and pelvis demonstrating considerable lymph nodes shrinkage. Bone scan remains clean (extensive metastatic disease in bones at diagnosis in 2013). PSA was 12.88 just prior to first round of docetaxel and after third infusion it reduced to.78. No other explanation for this reduction other than the chemo. Best to you

Gl448 profile image
Gl448 in reply to wagscure259

That’s great news. I wasn’t sure if you’d had scans after only three sessions.

Non PSMA avid pCA is DNPC or NEPC, negative for FOLH1 and AR. The pCA cells rely on GLUT1, they will be FDG avid. They will probably show DLL-3, lu177-DPRA-SC16 maybe a possibility in 2023.

pubmed.ncbi.nlm.nih.gov/318...

Largebill profile image
Largebill

The answer to any questions regarding prostate cancer that have absolutes (always or never) will be no. This disease behaves differently in each of us and responds differently to the various types of treatment for each of us. Having said that, the PSMA test should identify any active areas in your body. I just had a PSMA last month. They inject you with some radioactive stuff that is supposed to seek out any PC in our body. They wait about 45 minutes for the stuff to circulate in your body and then do the scan. Mine showed activity in my shoulder (scapula). As to PSA rise, that can be an indicator that something is going on, but PSA alone doesn't tell your doctor much. It can be an old metastatis or a completely new development. Best of luck going forward.

Benkaymel profile image
Benkaymel in reply to Largebill

"the PSMA test should identify any active areas in your body"

- this is what confuses me. I had a PSMA scan in January that showed PSMA avid tumours and my MO said that meant they were "active", BUT they are not growing. I thought active meant growing whereas PSMA avid just showed they were "regular" adenocarcinoma. Can someone clarify?

Chris52981 profile image
Chris52981

when you orginally get a biopsy it states which one correct? Could they change - are the other ones that are not adenocarcinoma harder to treat?

awb1 profile image
awb1

In my case, psma showed a single node in my neck when my PSA was .08. It was removed surgically. In another case of mine, psma showed 4 small lung nodules when my PSA was .06 and they were ablated with cryo by an interventional radiologist.. In another case of mine fdg showed a single node in my neck when PSA was .02 and it was removed surgically. I suppose if you have 10 micromets and a PSA of .05 you wouldn't see them with a psma, if there's a single node then you might see that one. A matter of concentration to some point of scan threshold. The fdg reveals small issues, it's nice to have history and the same radiologist reading to compare and looking for changes; progression and remission. I get one or the other scan every 3-4 months. I toss in a short series of taxotere every few years as a rinse. I'm on my own custom BAT and keeping my PSA < .006. I'm kind of weird in what I'm doing and work with an open-minded MO and a closed-minded MO, navigating between the rails, transparent with all. They trust me and learn as well.. I don't do clinical trials because I can't pivot and do my own thing. I'm probably disqualified from eating toast I've had so much stuff for 20 years. That's all I have to offer on this thread, thanks. Have a nice week.

Chris52981 profile image
Chris52981 in reply to awb1

wow makes me have hope! Are you Castrate resistant I assume

lewicki profile image
lewicki in reply to awb1

can I talk to you one on one?

awb1 profile image
awb1

I once was. ADT would kill me. Look up BAT. That's all from me on this thread, thanks.

Chris52981 profile image
Chris52981

yes my dads pathology was adenocarcinoma - just wondering if that can change later on meaning the cancer

You may also like...

PSMA PET Scan Question

your PSA is below 0.1 a PSMA PET scan isn’t useful because it requires a certain level of the PSA...

What’s the best PSMA scan.

asked about there PSMA scan. They offer the F18 PSMA, is the Pylarify better, or does it really...

psma pet scan available in Colorado?

Hello, Does anyone know if psma pet scans are available in Colorado or only in California? Thank...

Medicare Coverage for PSMA Scan

PET scan, and just found out that Medicare does not yet cover this cost ($3300). Does anyone know...

Accuracy of PSMA PET scan?

What would you venture to guess is the accuracy of the PSMA PET scan? How many of you showed \\"no...