Are Axumin scans worthless after brachytherapy? What about PSMA scans?

[Grumpyswife]

We finally found an MO who allowed my husband to have another Axumin scan to compare progression from a year earlier. He has been on Xtandi almost a year with still slightly decreasing psa (currently 5.5 down from 14.8).

The doc told us the lung and throat lesions were unchanged from the previous two scans but the radiologist report noted some uptake near the neck of the bladder. The MO mentioned this as a concern but then changed his mind as he compared the previous scans for us. He said the uptake was probably from some of the 50 or so brachy seeds implanted nearby ~5 years ago giving off (my word) artifact. The MO said not to worry about this since the psa is still declining.

However, I was flummoxed enough to forget to ask for a copy of the report. Now I will have to spend time getting that and the CD as well to study it for myself.

My question is whether any advanced scan is useful after having brachy or is it just an inexperienced reader?

[Grumpyswife]

Hey Nalakrats, I am sure you are enjoying your vacation and I am so jealous--daydreaming of Florida constantly.

RE lesions. Yes as they have shown up on all 3 Axumin scans. He had previous PCa lesions removed from his lung/lung lymph nodes and those were PCa positive. Those were found from a C 11 acetate scan which is similar to the Choline scan Dr. Kwon used. The MO reiterated that the current lesions cannot be safely radiated or removed due to their critical locations. So systemic treatment is it.

He just had a Guardant blood test which was inconclusive due to low volume of disease in the blood and/or current treatments which could be the Xtandi or perhaps Provenge.

The good news is that there is no bone disease shown. We know that he has PTEN loss and TMPRSS2 fusion which qualified him for nothing.

I will keep trying for the PSMA scan for Lutetium treatments which may be his next option--if he chooses to put himself through more. He has accepted his mortality but I haven't. He is the same age as you but not in as good of physical shape.

Thanks.

Mary

[Tall_Allen]

There is a man in my support group who had Axumin scans after brachytherapy. He also "lit up" in the prostate to a small degree, but his RO dismissed that as still having some inert cancer cells that have yet to be cleared from his system (he had brachy boost therapy 2 years ago).

The more important question is what you can do with this information? It sounds like he cannot have his visceral mets safely irradiated. With visceral mets, docetaxel seems to be a good next step.

[Grumpyswife in reply to Tall_Allen]

Thanks for that reminder. For some reason I always dismiss chemo when it is proven and is a qualifier for the US PSMA studies anyway.

[dac500 in reply to Tall_Allen]

I had brachytherapy in 2011. I had an extra-capsular recurrence in 2016 and lymph node metastasis this year. The 18F-DCFPyL PET/CT scan I had at NIH detected the lymph node metastasis, but there was no uptake from the prostate. Does this mean that no inert cancer cells left in my prostate?

[Tall_Allen in reply to dac500]

They were probably all cleared out. It can take several years. For me, it took 4-5 years.

[tango65]

Axumin PET/CT has been reported to have an incidence of false positive of 16 to 30%, so the scans need to be interpreted by an expert with a very good clinical experience. The Ga 68 PSMA is the most sensitive, it has a very low incidence of false positives, but it could be problems in detecting cancer around the bladder because the Ga68 PSMA is eliminated by the kidneys. I believe there is a PSMA scan, the 18 F PSMA 1007 which is excreted mainly by the liver, They use it in Heidelberg Germany. I do not know if anybody is using it in the USA.

ncbi.nlm.nih.gov/pubmed/292...

[Grumpyswife]

Thanks will look into that but I really don’t want to go to Germany as right now I am yearning for Florida.

[tango65 in reply to Grumpyswife]

I don't either but I may have to go next month.

I believe inert cancer cells do not show in the Axumin scans, The test is based in the active incorporation of radioactive fluciclovine by the cancer cells. If the cells are dead they will not uptake the fluciclovine.

I am not a radiologist so I may be wrong.

Perhaps you should proceed with obtaining a Ga 68 PSMA or DCFPYl PET/CT and see if the scan shows anything in the prostate. One of these tests will be necessary if you want to proceed in obtaining Lu 177 PSMA treatment.

There are clinical trials for these PET/CT scans. These are lists of all the trials in the USA:

clinicaltrials.gov/ct2/resu...

clinicaltrials.gov/ct2/resu...

[Break60]

Why would they be useless? They’re used to find mets anywhere in the body and are most accurate at Psa close to 2.0 as are all the latest ct pet tracers.

[GP24]

I have several lymph node mets and one seems to touch the bladder wall. It could be located on a Ga68 PSMA PET/CT.

You empty the bladder before the scan, this helps to locate this.