Tag: Pylarify

Day 5,615 – Doctor Call

On By DanIn imaging, Prostate Cancer, RecurrenceLeave a comment

As I was driving to the barber to get my hair cut (both of them), my phone rang. Normally, I avoid phone conversations when I’m driving—even the hands-free, Bluetooth variety—but when the Caller ID popped up on the infotainment screen as being the VA Medical Center, I answered because I thought it might be the Oncology scheduler calling to set up an appointment.

Instead, the call was from the urologist I met on Tuesday to talk about his research and efforts to pursue an Axumin scan. (I sent an email to him yesterday saying that I did a little legwork for him and learned that UCSD still does Axumin PET scans in case the VA didn’t.)

In a nutshell, he contacted the VA nuclear medicine department and, according to him, they were very elusive with him in saying whether they even had the ability to do the scan at the VA and, even if they did, if they would do it considering the PSMA PET scans have replaced it in their minds.

Then the doctor again put his faith in the PSMA PET scan and thought that the Axumin scan wouldn’t provide any useful information. He also mentioned that he looked at the 10% of patients not having PSMA protein and said, from his quick research, it seemed to only been identified in a single study. Unfortunately, that was said at a time when I was more focused on driving than listening, and I’m sure I didn’t fully understand what he was trying to convey.

I was finally able to safely park and give 100% of my attention to the conversation, and he said one other thing that puzzled me. He seemed confident that, because my PSA was rising, I did, in fact, have the PSMA protein. I’m not sure that I agree with that and need to do some digging.

We did talk about having a Pylarify PSMA PET scan which uses a different tracer than the 68-Ga-PSMA-11 PET scans. He thought that that could be a possibility, but wasn’t sure that the VA offered it yet. He knew it had been FDA-approved, but thought that the VA hadn’t developed the protocols for its use yet. I mentioned that when I spoke with UCSD yesterday, they said they had the ability to do Pylarify scans, too.

I asked him about how I might get a referral from him/the VA for me to get the scan on my own, and he thought that there may be a number of bureaucratic hoops to jump through to make that happen, including determining if something was “medically necessary.” He wasn’t exactly sure of the process, especially if I was going to use my own insurance (Medicare).

I just wanted him to confirm that, in his view, there was value in getting a scan to learn the location of the cancer and what it’s doing. He agreed.

I told him that my goal was to find the cancer and, if there were one or two lesions, to do spot radiation to knock them down if they’re in a suitable zapping location. That may help delay the start of ADT. (Or not. I’m not sure if they put patients on ADT when going after oligometastatic lesions.)

Finally, he did ask if I had been scheduled with the oncologist yet, and I have not. He was interested in hearing what they had to say about scans.

Needless to say, the waters have been muddied and I’m a little less confident that I know what’s going to happen next.

I’ll send him an email in the morning recapping our conversation, with an emphasis on his agreement that having a scan at this point is important. Translation: Medical necessity. I’ll also let him know that I’m open to trying any scan that he thinks will work.

I may also ask him to explain again why he is convinced that I have the PSMA protein and why he’s skeptical of the 10% number.

I’ll also try to connect with the oncology schedulers and get that appointment on the books.

I may also look at what it takes to get myself in as a patient at UCSD through either their urology or medical oncology departments. Because UCSD did my salvage radiation therapy in 2022, I may still be in their system, so it may be less difficult than starting from scratch. I’ll have to figure out how to share my VA health records with UCSD if needed.

The saga goes on…

Be well.

Header image: Anza-Borrego Desert, California

Month 184 – PSMA Explained & Next Steps

On By DanIn Hormone Therapy, imaging, Prostate Cancer6 Comments

After last week’s PSMA PET scan, I did a little more digging into how the scans work, and why they don’t work for 10% to 20% of patients.

Prostate specific membrane antigen (PSMA) is a protein that’s found in healthy prostate cells, and it continues to exist in prostate cancer cells in most, but not all, cases.

PSMA in Imaging

Researchers found a way to attach a radioactive tracer to the PSMA proteins which would light up when seen in a PET scan, indicating the presence of cancer. Gallium-68 is the most commonly used tracer, with fluorine-18 also being used.

When the tracer is injected into the patient, it seeks out cells that have expressed the PSMA protein and attaches to them. The PET scanner then looks for areas where there is a build-up of the tracer to indicate where the cancer is located.

I’m going to use a grossly over-simplified analogy based on my reading as a lay person.

We all know that magnets are attracted to steel or iron. Imagine that the cancer cells with the PSMA protein are small steel ball bearings, and the radioactive tracer is a bunch of tiny magnets. Inject the magnets into your system, and they go in search of the steel ball bearings. When they find them, they attach, and the PET scan can see where all the magnets are located.

But for those patients whose cancer cells do not have the PSMA protein, that essentially means that the cancer cells are plastic balls, and the magnets that were injected will never attach to them. The PET scan won’t see any build-up of magnets/cancer cells.

Based on my experience with four PSMA PET scans, I believe that I’m in that 10% group and that my cancer cells do not express the PSMA protein—they’re the plastic balls.

PSMA in Treatment

In addition to using PSMA positive cells for imaging purposes, researchers have also recently developed a treatment that uses the PSMA positive cells. It goes by the brand name Pluvicto, but also known as Lutetium-177–PSMA-617.

It’s only used on patients with castration-resistant prostate cancer that have PSMA proteins.

The difference between using gallium-68 or fluorine-18 and lutetium-177 is that the lutetium is a radioactive material that attaches to the PSMA protein cells and delivers beta particle radiation to kill the cells.

This means that for those patients whose cancer doesn’t express the PSMA protein, this treatment option would not be available.

Alternative Imaging

On the good news front, there are other imaging options out there, one of which is Axumin (18F-fluciclovine). Instead of targeting PSMA in the cancer cells, it looks at the amino acids.

Axumin scans aren’t as sensitive as PSMA PET scans, but they are more sensitive than choline-11 scans.

At my current PSA level (2.52 ng/mL), the Axumin scan should have a decent chance of finding something.

In a conversation in a prostate cancer forum, I learned that one patient had used the gallium-68 tracer for his PSMA PET scans with the same results as mine, but they switched to PYLARIFY (piflufolastat F 18) as the tracer (which also attaches to the PSMA) and found four lesions using the different radiotracer. I know that one anecdotal case doesn’t mean much, but it’s something I can ask my team about.

Skip Imaging?

You may recall that, at one point, I had conflicting guidance from the urologist and oncologist on when to start androgen deprivation (hormone) therapy (ADT). One said when we saw metastasis, and the other said when my PSA hit 2.0 ng/mL. Clearly, I’ve passed the 2.0 threshold with my latest PSA results.

I went back and recalculated my PSA doubling time using only the last four values dating back to 10 March 2025. (The fourth and fifth values that I used before are 0.94 (January 2025) and 0.95 (March 2025), so having them so close may have skewed the results a little. When I used all five data points, my PSADT was 10.1 months; when I use the last four data points, it’s 8.9 months.

Given I’m past the PSA threshold (for one doctor) and the fact my PSADT is less than 10 months, I’m also wondering if there’s any value in continuing in the efforts to try and find the lesions. Or is is better, given how my PSA is increasing, to go ahead and just resign myself to the fact that I have micrometastases someplace and start the ADT sooner rather than later? In the time that it takes to schedule another scan, regardless of the type, my PSA could be well over 3.0 and even pushing 4.0.

That leads me to another question. If we do start the ADT and it knocks my PSA down to <0.1 like it did when I had it for salvage radiation therapy, does that mean that scans wouldn’t be able to locate the cancer while on ADT?

To my way of thinking, knowing where the cancer is at is important, even if it means letting the PSA run unabated for a short while longer. But what the hell do I know? I’m all ears for experiences from others that may have been in the same or similar situation.

Summary

Again, this is my lay person interpretation of things that I’ve researched, so please take this with a pound of salt. If you know I’m wrong on my interpretation, please let me know and provide references as to why I’m wrong. I want to learn.

You can rest assured, though, that this will be a part of my conversation with my team on 24 March.

Stay tuned for more.

Be well.

Header image: Desert wildflowers, Anza-Borrego Desert State Park, California