Can PSMA PET scans replace the need for bone and CT scans?

A new review article suggests the possibility that radiolabeled prostate specific membrane antigens (PSMAs) and PET scans may, at some point in the not too distant future, replace bone and CT scans in diagnosis and monitoring of men with advanced forms of prostate cancer.

The article by Maurer et al. (a group of German researchers) in Nature Reviews: Urology lays out why the authors feel that current research on gallium-68-labeled PSMA and other forms of radiolabeled PSMA, and associated PET scanning, provides superior data on patient risk for metastatic forms of prostate cancer — inclusive of smaller amounts of metastatic prostate cancer not previously well imaged using traditional forms of bone scan and CT scan.

From a clinical perspective, The “New” Prostate Cancer InfoLink would concur with the authors that these new forms of imaging do look very promising, and would certainly be beneficial in the management of patients who are not currently well served by older forms of imaging. On the other hand, from a cost perspective, this could be a worrisome trend. PET scans are costly (at least, they are very costly here in the USA) and access to PET scanners is far from universal.

The potential use of gallium-68-labeled PSMAs and other newer radiotracers along with PET scans is well-defined groups of patients still needs to be more fully evaluated before anyone will be ready to make decisions about the widespread clinical application of such technology in the diagnosis, work-up, and long-term management of men with prostate cancer, but the promise is certainly “out there”.

4 Responses

  1. I am from Germany and last year had a PSMA PET/CT done. The urologist had send me for a bone scan and I asked the clinic whether a PSMA PET/CT would be better. They said: “Boy, you are right let’s do PSMA PET/CT.” Basically any clinic which has a PET/CT can order the PSMA tracer from a special lab and do a PSMA PET/CT once they are approved for that.

    On the previous MRI they had found two nodes close to the prostate and the PSMA PET/CT found a third one. But it also made sure there were no more metastises, e.g., in bones.

    This year I had a PSMA PET/MRT done since the SBRT center insisted on checking whether the primary tumor was successfully removed before addressing any metastasis with SBRT. So they found a fourth node this time.

    As discussed with other patients in Germany, when you do a PSMA PET/CT you quickly end up in a metastatic situation since it is so sensitive. Before this you had your prostate removed, thought you were done with it, and then wondered why the PSA level was rising. Then you are told there is basically no cure for you.

    So you have to look into various local therapies now while doing ADT. I know a lot about oligometastasis now.

  2. Dear Georg:

    It’s a lot harder to get a PSMA PET/CT scan done in most of the world than it seems to be in Germany! And I don’t think they are necessarily something one wants to recommend for the majority of men (with low-risk prostate cancer).

  3. Dear Sitemaster,

    Quite a number of men have a double-digit PSA level at first test. I then would recommend a PSMA PET/CT after the biopsy proved cancer. I think you should know as much as possible about the extend of your disease and then decide how to treat it.

    Of course doctors also have to adjust to more oligometastatic treatment. Not every patient can be treated by Dr. Kwon.

    In Germany a PSMA PET/CT costs much less than a monthly package of enzalutamide.


  4. I encourage patients who find themselves in a situation where detection of metastases might be useful (and that is arguably limited to cases where it is too early for a bone scan, and it is necessary to rule out locoregional treatment as futile) to participate in clinical trials. In the US there are many such clinical trials, notably at NIH, Johns Hopkins, Stanford, Emory, UCSF, UCLA, MSKCC, Weill Cornell, etc. Trials use a variety of positron emitters and a variety of prostate cancer-specific ligands. They may also increase sensitivity using the combination of PET and MRI. The nice thing about clinical trials is that they are often free to the patients. The downside is that they are experimental and their use has not yet been validated.

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