PSMA PET CT Imaging Sensitivity

If I’m understanding this correctly, PSMA detects cancer at the recurrence definition of .2, positively, 20% of the time with a probable percentage of close to 50% of the time.

PSA between .2 and .3....PSMA detects cancer “positively” at just over 50% of the time. (With another 20% of “probables”....meaning....with a PSA of between .2 to .3....PSMA picks up “probable” cancer 70% of the time).

At least in this particular cohort of 70 men.

Fairwind said...
And this scan costs how much ?? Does this greatly increased cost offer a survival benefit over slightly less sensitive scans ? Once the horse has left the barn, how important is it to know exactly when he left ?? Will this knowledge result in a better chance for a CURE ??

I do not know the answer to these questions. My thinking is...the more precise the scan, the clearer the distinction becomes between those who *can’t* be cured verses those who might can be cured.

In other words, the more precise scans become, the clearer the choices going forward becomes.


.

Post Edited (island time) : 10/20/2019 10:52:56 AM (GMT-6)

Got the axumin PET scan done with fluciclovine F18 about 2 months ago. The PET scan found 2 enlarged 'hot' lymph glands. Had a bone scan done last year that found no mets. I just had a consult with a radiation oncologist this past Monday to see if they were reachable with a proton beam or IMRT as per

https://prostatecancerfree.org/pca-commentary-139-oligometastatic-prostate-cancer-is-it-an-intermediate-stage-of-cancer-and-if-so-how-should-it-be-treated/

He is going to get back to me in a short while to let me know if this can be done. I will be back on leuprolide chemo this week, but am game to get the mets zapped if possible.

" an immunologic response was recorded in the SABR cohort in the form of an increase in activated T-cells. Presumably this was a result of the exposure of neo-antigens resulting from radiation induced cell death."

Once the horses have left the barn, finding and zapping the big horses, perhaps reducing the PSA to undetectable, is a feel-good exercise. The little baby horses are still running loose and sooner or later they will be back and this time they will be much tougher to deal with..When the PSA returns that second time, treatment is usually focused on extending the life of the patient as long as possible while maintaining his quality of life as much as possible. Different Oncologists have different viewpoints as to how to accomplish this.

I put up the original post just because i felt it would be of interest to many, apparently it is. At least worthy of discussion.
As i recall, multiple studies are underway in the U.S. Here's one such study.... which looked at men with BCR recurrence and PSA between .2 and 2.0 ...
https://www.renalandurologynews.com/home/news/urology/prostate-cancer/pet-ct-imaging-for-recurrent-pca-detection-more-accurate-with-psma

"Jeremie Calais, MD, of UCLA, and colleagues compared the scanning modalities in 50 consecutive patients with biochemical recurrence (BCR) and PSA levels of ≥0.2 to ≤2.0 ng/mL. All patients underwent PSMA and fluciclovine PET/CT scans within a median time interval of 6 days. Each scan was interpreted by 3 independent blinded expert readers not involved in study and data acquisition.

Detection rates were significantly lower with fluciclovine than PSMA PET/CT per-patient (26% vs 56%; P = 0.003), per-region for pelvic nodes (8% vs 30%; P = 0.003), and any extra-pelvic lesions (0% vs 16%; P = 0.008), Dr Calais and his collaborators reported in a poster presentation. In addition, reader agreement for PSMA PET/CT image interpretations was significantly higher than for fluciclovine PET/CT (0.67 vs 0.20; P = 0.015)."

I looked at PSMA Gallium PET personally, when i was considering to do SRT or not. I was not eligible for the trials available as my PSA was .08, below the threshold for all the trials. My URO offered to hook me up with a hospital in Germany, WHERE IT IS ALREADY APPROVED. I thought about it, but decided against it as from all i had read (and still read) the chance of finding anything with a PSA of .08 would be very very small.

here's an interesting article from Jan 19.

of positive carbon-11-choline PET/CT results in the therapeutic management of prostate cancer biochemical relapse
Gómez-de la Fuente, Francisco J.; Martínez-Rodríguez, Isabel; De Arcocha-Torres, Maria; Quirce, Remedios; Jiménez-Bonilla, Julio; Martínez-Amador, Néstor; Sánchez-Salmón, Aida; Lucas-Velázquez, Blanca; Cuenca-Vera, Oriana; Banzo, Ignacio

Nuclear Medicine Communications: January 2019 - Volume 40 - Issue 1 - p 79–85
doi: 10.1097/MNM.0000000000000936
ORIGINAL ARTICLES
BUY
Abstract
Author Information
Article Metrics
Objective Carbon-11-(11C)-choline PET/computed tomography (CT) has shown good results in re-staging of prostate cancer (PCa) with raised serum levels of prostate-specific antigen. Our aim was to evaluate the effect of positive 11C-choline PET/CT results in the therapeutic management of patients with PCa with biochemical relapse (BR) after curative intention treatment.

Patients and methods A total of 112 patients with PCa BR and positive 11C-choline PET/CT were retrospectively evaluated. PET/CT was acquired 20 min after intravenous administration of 555–740 MBq of 11C-choline. The therapeutic management after 11C-choline PET/CT was obtained from the clinical records. The minimum follow-up time was 18 months.

Results In 80 (71.4%) of 112 patients, 11C-choline PET/CT showed local recurrence of PCa; in 17 (15.2%) patients, distant recurrence; and in 15 (13.4%) patients, local plus distant recurrence. A second malignancy was detected in five (4.5%) patients. The planned therapeutic management was changed as per positive 11C-choline PET/CT result in 74 (66.1%) patients and were treated as follows: 31 (27.7%) patients with HT, combined with other treatments in eight (7.1%), 17 (15.2%) with BT, 13 (11.6%) with external beam radiotherapy, one (0.9%) with RP, and four (3.6%) with chemotherapy. Treatment approach was not modified in 37 (33%) patients. No data was available from one (0.9%) patient.

Conclusion Positive 11C-choline PET/CT result had an important effect in the therapeutic management of patients with PCa and BR, leading to a change in the planned approach in two (66.1%) out of three patients. In addition, in 4.5% of the patients, the 11C-choline PET/CT allowed the detection of a second malignancy.

Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.
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Maybe one of computer tech guys can put a link to it? Thnx

You guys have spent a lot of time studying this issue! I am enrolled in the Mayo PSMA vs choline 11 study. That's why I waited so long to get the scans. The study stopped for a couple of months for reasons they didn't tell me. I would rather have had the scans when my PSA was around 1. Now that I know the greater sensitivity of PSMA if, may God forbid it, I have another recurrence I will ask for a PSMA scan at .2 or .3 (if the study is still ongoing or PSMA is approved). I would like to fight mets one at a time as long as I can. If a scan eventually shows up with 10 or 20 mets there will not be a reason for these scans any more. If I may use an analogy, if a graffito shows up on your wall wash it off right away and possibly more won't be put there. I did that when I lived in town. We never had another. Ignore it and very likely soon your wall will be covered with graffiti.

You will treat mets mostly with SBRT radiation. This is an approved treatment. You can repeat the radiation if cells show up at different areas in the body. So you do not radiate the same area twice:
https://ro-journal.biomedcentral.com/articles/10.1186/1748-717x-9-135

IT,
My MO has always said that no one really knows if starting ADT earlier or later is better for guys with systemic mets. The TOAD study showed that earlier use is better, but my understanding is that it's considered to be a weak study. His view is to wait as long as reasonably possible to start ADT. He uses PSA doubling time, presence of physical symptoms, or radiological evidence of mets as factors in the decision for initiation of ADT. In the past, bone scans and CT scans have provided the evidence for mets. The newer, more sensitive scans are showing mets earlier. Patient comfort with an increasing PSA is also a factor.

mattam and George.....

Thanks to both of you for your replys. mattam….your RO's take kind'a squares with what information I've been able to distill. That the jury is still kind of out on ADT. And that Doubling Times are of paramount importance. I believe that to be the case. It just makes sense.

George......thank you too, so much, for the information on UT and Ashville (Ashville is a beautiful 80 minute drive through the mountains from here). And I hear you about "not asking their recommendations" Although it can be tough, going against what are supposedly the experts in any endeavor. Medicine in particular. It's very tough.


Opinions from centers of excellence are good. We already know about JH. I do not believe my siblings will want to go there for this. I believe she is going to want MD Anderson. They cured her Breast cancer 30 years ago. They've cured other of my family members of other cancers. We've had good luck at MD.

It just seems to me like (rightly or wrongly)…..one is better off keeping the powder dry for as long as possible. And laying off the ADT until pain, doubling time or the number of mets becomes too much. No telling what the PSA might look like. But somethin' tells me....and I can't honestly say exactly why or what makes me believe this...that PSA (the number in itself....in a vacuum) may be on down the list going into this. But...that's just me. And...it seems to be working for a number of people.

(My only goal is to have some kind of direction when my sister comes callin' about her husband. Just directions to point....it'll be their decisions and own research that they make decisions with)

thanks guys. I'll be in touch lol

(I've even considered going this route for myself...should SRT ever be needed. But, I'll cross that bridge if I arrive at it)

Im_Patient said...

.....Docs are all advising going on treatment of some kind, despite no positive indication of disease (post-prostatectomy / post-SRT).
Jeff

Not surprising....that's what they're trained to do, and paid for.

Argent, I don't doubt that I have PCa. The main point of my post is that there are some deliberating about a scan at 0.2 PSA or thereabouts... there is no assurance that they will be able to find the cancer. I was hoping, as you said, that it would find a concentration that we could zap. Seems that there are not enough of a collection to find yet. I am not in a hurry to go on treatment, but plan to. I might wait and go for another scan (this one will be covered by insurance though - whatever it is). Jeff