PSMA Scan with PSA<0.006

[Karmaji]

Seeking opinion of members

regarding utility of psma Scan with Psa <0.006 since 2 years .

I had oligometastatic 2 spots on pelvis. These were targeted during RT in nov 2019.

This month Choline Pet Scan

was all clear.

Any comments ?

Thanks ......

[swwags]

I didn't know there were PSA tests out there that read to the third decimal. At any rate, with a PSA that low, assuming your cancer is PSMA avid, the scan wouldn't show anything. Most clinics indicate scans when PSA reaches 2.0.

[dac500 in reply to swwags]

Some labs measure PSA up to the third decimal. My lab does and I get results like 0.453 etc.

[TJGuy in reply to swwags]

Labcorp ultrasensitive goes to <0.006

[Tall_Allen]

Useless.

[Karmaji]

Thanks sw Ta Nal...

[GP24]

A PSMA PET/CT is more sensitive than a Choline PET/CT. So instead of a Choline PET/CT I would get a PSMA PET/CT. However, you have to ask yourself what therapy you plan to get after the result? I guess you are on ADT now and this stops the tumor from growing.

[Hidden]

In this case its great….for the team that will collect your money! For you, not so much.

[dac500]

If your PSA is <0.006 for the last two years, then why rush into PET/CT scan?

[Hidden]

Spend some time, some money, and get some radiation? No thanks. Your PSA is too low, sorry to break the bad news

Let your MO decide but in general, there is no utility to scans when your PSA is less than 0.3 or so.

[RusLand]

As a person who has passed more than a dozen PET-CT studies (68Ga-PSMA-11, 18 F-PSMA-1007, 18F-FDG, 68Ga-FAPI) over the past two years, I can assure you that with your PSA level, this examination will not bring you any information! The most informative study with low PSA values for prostate cancer, of those that I personally passed.. - this is a survey using RFP 18F-PSMA-1007 on a scanner with a resolution of more than 5 mm. But even this study will not be informative with a PSA of less than 0.2 ng/ml! If there is a possibility of replacing a diagnostic radiopharmaceutical, then I would personally, in your case, undergo a PET-CT examination with rfp 18F-FDG to detect glycolysis in malignantly transformed cells. It was found that glucose metabolism in low-differentiated hormone-refractory cells is higher than inhighly differentiated hormone-sensitive cells. The presence of this correlation between the aggressiveness of the tumor and the level of glycolysis allows to use the results of PET with 18F-FDG for an accurate assessment of therapeutic efficacy of chemo, hormonal, radiation and radionuclide, radioligand and other therapies. The results of this study may be useful to you in the future! If it is not possible to carry out this particular examination, then you should not expose your body to excessive radiation! As Nal advised you, tracking the dynamics of the PSA paired with the T is quite enough! Good luck to you and God bless us all!

[dhccpa in reply to RusLand]

You are the PET Scan meister! I've had four now, 3 of them Axumin. The last showed higher uptake in what had been (over 3 years) my largest met, in my hip (overall background uptake was up by a similar percentage). However, my MRI done at same time failed to find that met, even though it had shown on every single scan over 3 years (MRIs, Cats, nuclear bone scans). So I've wondered about SUV preciseness at times. Any confounding results on your part?

[RusLand in reply to dhccpa]

Hi! Unfortunately, there is very little information to answer you more precisely..(( MRI is good for soft tissue imaging, but not very informative when diagnosing bones.. In this case, if there are doubts about the interpretation of the results of PET-CT studies, then it is necessary to turn to the dynamics of PSA. In our case, this antigen serves as a good indicator of changes in metabolic activity in malignant foci! If your PSA has grown between the last two PET-CT examinations, then there is no reason not to trust the extreme examination! It should also be taken into account that different PET-CT scanners have different resolutions and even scanners of the same model may have different calibration values of the SUV.. Therefore, if possible, it is necessary to undergo this study on the same PET-CT equipment. Here in this picture you can compare how the PSA value changes with the change in the absorption of the PSMA ligand by a malignant focus by the value of SUV (luminescence intensity):

Change of PSA values in dynamics with the intensity of PSMA accumulation

[GP24 in reply to RusLand]

Did the 68Ga-FAPI scan show prostate cancer?

[RusLand in reply to GP24]

The Baku Nuclear Medicine Center has been working in close cooperation with the Cancer Institute in Heidelberg (Germany) since 2016 and actively participates in all clinical studies related to the use of various biological carrier molecules and new radioisotopes. Last year, this center of excellence conducted a study of a new FAPI molecule paired with 68Ga for PET-CT imaging of breast cancer foci in 100 patients with a confirmed diagnosis. Using my friendly relations with the head of this center, I volunteered with four of my prostate cancer patients to undergo a PET-CT examination with rfp 68Ga-FAPI. Interim results of studies of 100 patients with breast cancer and 5 patients with prostate cancer - reliably indicated the fact that the new FAPI molecule accumulates exclusively in those foci where FDG accumulates and practically does not accumulate in foci negative to FDG, both in men and women! Of the five patients with prostate cancer, two were with a negative status to FDG, and three patients had a positive status to FDG. FAPI accumulated exclusively in those foci in three patients who absorbed FDG and did not accumulate at all in malignant foci in two patients with a negative status to FDG! It should be noted that the FAPI malecule is not expressed on the surface of malignant cells, but targets the intercellular substance around such cells. Thus, the damaging effect of radiation on malignant cells will be many times more effective and will not allow new cells to develop in this radioactive environment! And the big plus of the new carrier is the fact that it practically has no physiological accumulation sites, and therefore the side effects associated with this when using it for therapeutic purposes will be significantly less! To date, this new molecule is predicted to treat 28 types of cancers! It also gives great hope to those patients who were not helped by treatment using 177Lu-PSMA! My status to FDG is negative and here are my PET-CT results with 68Ga-FAPI.. My status to FAPI also turned out to be negative with a total lesion of my bones. You can independently compare with the results of my examination with 68Ga-PSMA in the picture above:

My PET-CT study with 68Ga-FAPI

[GP24 in reply to RusLand]

I also got an FAPI PET/CT last year. It did not show any metastases while a PSMA PET/CT two months later did show five of them. So my experience is that it is not as sensitive as a PSMA PET/CT. The clinic used FAPI PET/CT for breast cancer.

You compare the results of an FDG PET/CT with an FAPI PET/CT. Did you find that an FAPI PET/CT is more sensitive than an FDG PET/CT or are they about the same?

I think FAPI is not completely specific for cancer. Here is an image of an FAPI PET/CT used to visualize rheumatoid athritis.

FAPI PET/CT image showing arthritis

[TEBozo]

Sounds really good. The PSMA is Ultra sensitive so all is well. Continue to scan over your lifetime so if a micro metastasis pops up you can treat with radiation.

[PGDuan]

I don't think scans will be useful right now.

I just finished 3 scans (trial PSMA PET scans with two new different tracers, R2 and NeoBomb, and an Axumin scan). "Nothing treatable" was observed. My BCR PSA was 0.3 at time of the PSMA scan, and 0.45 at time of the Axumin scan 2 months later.

PSA has risen to 0.77 now, so perhaps another scan soon will identify the source.

[EdBar]

PSMA is not a good option until PSA reaches 0.5 or higher. My MO, Dr. Sartor, told me he might want to have me get a PSMA scan once I hit a PSA level of 0.1 - 0.2 because I’ve been on ADT for 8 years and my non detectable PSA has recently become detectable again although still at an extremely low level. He said it’s possible to have cancer with a suppressed PSA after long term heavy treatment that could show up on a PSMA scan.

Ed

[slpdvmmd]

I read comments below. My personal experience is my PSA had been at .042 for sometime when in Feb 2021 it began to go up by June was 0.74. Got PSMA PET/CT that defined three PSMA avid nodes in my left neck. Was treated with Lu177/Act226 in Heidelberg as well as fractioned IMRT. PSA now below level of lab. So certainly it is my experience that there can be significant findings with PSMA PET/CT that were missed on prior scans including standard CT and Axumin with PSA substantially lower than 2.

[MateoBeach]

PSMA PET for screening or diagnosing new mets would require a PSA somewhat north of 0.2 to be expected to show anything. This does not apply to you since you want to follow up on the treated nodes. You can see if they have disappeared (entirely or partially) and also check for any new visible sites.I had RT to two pelvic nodes and RT to that pelvic field treated in 2019. I have annual followup PSMA scans since. The most recent one was this month which showed two new sites of PSMA positive nodes. So now I am arranging further treatment. It is very useful. I think you should request the PSMA scan as it might change your treatment approach as it did for me.

[MateoBeach]

However, see my reply, Nal.

[Break60]

Yeah your cancer free for all intents and purposes.

[Karmaji]

Many thanks friendsIt seems for low psa <0.1

Scans give no useful information...

May be my Choline scan was useless for psa<0.006

But my onco says one should have scan every year..

In France PSMA scan is still

in less availability.....soon it may become gold standard for detecting...

I agree avoid useless scans

if they give no information