PSMA PET finds more cancer than Axumin - Advanced Prostate...

Advanced Prostate Cancer

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PSMA PET finds more cancer than Axumin

Tall_Allen profile image
27 Replies

This is for the Ga-68-PSMA-11 PET/CT scan. It was especially good at detecting cancer in the pelvic lymph nodes.

pcnrv.blogspot.com/2019/08/...

(I edited my blog to highlight the importance of the finding that the pelvic lymph nodes were the principal sites of recurrence. This is potentially a game changer.)

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Tall_Allen profile image
Tall_Allen
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27 Replies
cesanon profile image
cesanon

Is there anything that Axumin is better suited to do than the PMSA scans?

Tall_Allen profile image
Tall_Allen in reply to cesanon

Not that I'm aware of. But it would be interesting to see a comparison in high risk patients. I might hypothesize that Axumin may lose some of its utility in end-stage PC - but they would have to test that.

cesanon profile image
cesanon in reply to Tall_Allen

Axumin does catch some non-PSMA sensitive cancer that PSMA ligands miss, doesn't it?

Tall_Allen profile image
Tall_Allen in reply to cesanon

Both had the same rate of false negatives, but the numbers were small.

cesanon profile image
cesanon in reply to Tall_Allen

It seems like what PSMA misses, Auximin may catch.

It would seem to make sense to try a PSMA scan. Then if it comes up negative, try an Axumin scan, just to make sure that you don't have the non-psma sensitive prostate cancer?

Wouldn't that make sense? Especially if the Auximin happens to be covered?

Tall_Allen profile image
Tall_Allen in reply to cesanon

Not to me- the PSMA is more sensitive - I'd go for that. FDG might show the kinds of tumors that don't show up with either, but for what purpose?

cesanon profile image
cesanon in reply to Tall_Allen

1. What is "FDG"?

2. If PSMA misses prostate cancer cells that are not PSMA sensitive, it seems it would make sense to somehow test for such non-PSMA sensitive prostate cancer cells. In order to avoid any false negatives.

3. "I'd go for that. FDG might show the kinds of tumors that don't show up with either, but for what purpose?" To avoid false negatives?

Tall_Allen profile image
Tall_Allen in reply to cesanon

FDG is the kind of metabolic indicator that is more likely to show up at later stages or in rare cancers that the others won't pick up. Axumin and Choline scans rely on the metabolism used by common acinar adenocarcinoma of the prostate - the same kind PSMA would pick up. But the point is: if only FDG shows them, you would already be well aware that you have such tumors - you'd have felt them and seen them on a CT scan, and certain biomarkers would have shown up. This study was about earlier detection - and PSMA seems to be the best at early detection.

There is nothing to indicate that Axumin can pick up what PSMA won't. In fact, the opposite seems to be true. You can spend lots of money and needlessly expose yourself to low levels of whole-body radiation using - but to what purpose? PET scans - even the best of them - will not see anything less than 4 mm - which will be the size of many mets.

E2-Guy profile image
E2-Guy in reply to Tall_Allen

Very interesting info!

Two years ago trying to decide between the two scans was difficult. Prior to finally deciding on the 68Ga I consulted with five specialists and the jury was still out. My decision was determined by the less expensive of the two...$600 US in Melbourne, AU.

tallguy2 profile image
tallguy2

Thanks for posting this.

rust profile image
rust

I paid for 2 FACBC scans in the last 18 months and was fortunate to be imaged with Ga68 PSMA-11 last week as part of a clnical Phase 2 trial with confirmed diagnosis of nodal disease.

cesanon profile image
cesanon in reply to rust

What is a "FACBC " scan?

rust profile image
rust in reply to cesanon

Fluciclovine (18F), also known as anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid (FACBC),[1][2] or as Axumin (brand name)

KingNeptune profile image
KingNeptune

I had both scans, the Axumin was first, followed by two back to back PSMA scans to establish a base line. I then started ADT with Zytiga and went back for another PSMA scan about four weeks later to see the results. The Axumin showed one hot spot, but the PSMA scan lit up like a Christmas tree. The follow up scan showed no mets. I had this done as part of a clinical trial at University Hospitals Seidman Cancer Center in Cleveland Ohio two years ago. So for me PSMA is the way to go.

sjc2 profile image
sjc2 in reply to KingNeptune

I'm confused... why would you say "So for me PSMA is the way to go" if the first PSMA scan "lit up like a Christmas tree" and then the follow up scan "showed no mets"? Doesn't that mean the PSMA gave you a false positive reading on the first scan?? Just trying to understand since my hubby had the Axumin and it only showed one very small pelvic lymph node and we were so happy it didn't show more, since we thought this was a great scan for his recurrence.

Tall_Allen profile image
Tall_Allen in reply to sjc2

The Zytiga shrank his mets. That’s what it’s supposed to do.

KingNeptune profile image
KingNeptune in reply to sjc2

Hell no.......!!! Started ADT and Zytiga for the third scan.......please reread my post. This is from the horses mouth, and the trial, don’t waste your money on the Axumin. Listen to TA......

cesanon profile image
cesanon

"All men had post-prostatectomy PSA from 0.2- 2.0 ng/ml."

Any reason to believe that the results would have been different if the ng/ml levels had been higher?

"The other PSMA-based PET scan, DCFPyL, has completed recruiting in some locations."

Any reason to believe that the DCFPyL would be better or worse than the Ga-68-PSMA-11 PET/CT scan?

PS: By the way, thanks for the constant stream of the most current high quality prostate cancer information.

Tall_Allen profile image
Tall_Allen in reply to cesanon

Yes, detection rates go up with PSA.

DCFPyL has higher detection rates than Ga-68-PSMA-11 at the same PSAs:

pcnrv.blogspot.com/2019/08/...

PGDuan profile image
PGDuan

Interesting report.

Ironically, I had a trial "R&D" GA-68 PSMA scan completed at Stanford last year before RALP as nothing was detected outside the prostate and I was GS 4+3. Given a post-RALP PSA of 4 despite 0/15 positive lymph nodes, I then had an "official" Axumin scan that noted two avid lymph nodes as the likely culprits. EBRT and ADT now seem to have cleaned things up.

Given the PSMA is more sensitive, my guess has been that either 1) the RALP missed some the prostate issue, or 2) the R&D PSMA PET was not "read" rigorously enough and thus missed the PCa outside the prostate. Any other guesses?

Most likely #2, so here is my advice: if you get a trial "R&D" PSMA scan proceed with caution.

Tall_Allen profile image
Tall_Allen in reply to PGDuan

I agree - the experience of the radiologist is critical. In this study, "Each PET scan was interpreted by three independent masked readers and a consensus majority interpretation was generated (two vs one) to determine positive findings." In this study, the readers of the PSMA were European and had more experience with the PSMA scan (in Europe, salvage LN treatment is often surgical, so they can learn with more immediate feedback), so inter-observer variation was lower for the PSMA scan. But neophyte readers can make big mistakes.

Should be the first test given to anyone with a high enough psa to rule in or out everything else.

blueCello profile image
blueCello

My husband's radiologist really wanted the Axumin scan to pinpoint spots for her treatment. But he was already stage four and she had to throw up her hands that he was too far gone. Insurance would not cover it until I fought like a tiger for about eight months. Why a doctor's judgment should not trump (excuse the expression) an insurance company's is beyond me.

Tall_Allen profile image
Tall_Allen in reply to blueCello

Don't get me started on insurance companies! We'll have to see if the 2020 elections results in their demise (or at least, reduction).

blueCello profile image
blueCello

We certainly need big changes in our healthcare system, ones in which patients needs come first; not profits! You hear stuff like cancer is a $300 billion a year BUSINESS and it makes me sick that those dear ones around us who are ill are pawns in this travesty.

TJGuy profile image
TJGuy

I participated in the UCLA to get Lu-177 PSMA scan approved. Then then participated in a MAYO trial Choline vs PSMA GA68, the trial results were that for some patients( a small subset) Choline showed brighter, but for the majority PSMA showed brighter. They both found the same points.

Except Choline also found inflammation from a hard fall on my lower back. A false positive in this case.

It was read as a false positive by the experienced MAYO staff.

So not everyone has PSMA less than 10% of patients don't have PSMA so alternate scans should be looked at for these patients. And until you find this out perhaps dule scans are appropriate at some point.

Tall_Allen profile image
Tall_Allen in reply to TJGuy

IMO, Choline is a thing of the past, even though Mayo is still trying to retrieve their investment. But NaF18 shows twice as many bone metastases as PSMA. And I think getting an FDG PET is a good idea for anyone getting a PSMA PET prior to Lu177PSMA treatment post-chemo and ARSi failure. So I agree that two PET scans may sometimes be a good idea.

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