Practice Updates in Prostate Cancer Imaging - Episode 8

Key Messages from the OSPREY Trial

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Authors from the OSPREY clinical trial highlight the key take-home messages from the trial outcomes.

Neal Shore, MD, FACS: What are the key take-home messages from OSPREY? Larry, please, and then Mike since you guys were both investigators and authors in the trial.

Lawrence Saperstein, MD: Mike hit on the high points, high specificity, positive predictive value. We know now this is a valuable tool for defining metastatic disease, notal or distant metastases, in this high-risk patient and ultimately may spare patients unnecessary surgery. That’s a take-home point for me.

Michael Gorin, MD: The exact same take-home points, the tremendously high positive predictive value because of the high specificity. You know that if something is positive on this scan, again, with some caveats, that virtually always it’s going to be prostate cancer. And if you have a patient whom you image with the test and you see that they have things that make sense for metastasis, they’re in the right anatomic location, they’ve got high Gleason score and so forth, you could believe the results of this scan and that was very clearly demonstrated in this trial.

Neal Shore, MD, FACS: Absolutely. And the reimbursement is there too. There’s always lag in reimbursement with accessibility. This is important. We’ve made great strides in the last year. And this just is another reminder of how very recently the FDA approved the second PSMA [prostate specific membrane antigen] targeted study or targeted application. The F18, that was in May of this year. The earlier December 2020 was just for the gallium in UCSF [University of California, San Francisco] and UCLA [University of California, Los Angeles]. But then most recently in December of this year, the gallium had also received a national FDA approval. And essentially, the indication is for any form of biochemical relapse, regardless of the stage of the disease, which is an important issue and for high-risk localized patients as well. That gives it a broad application. Mike, let me throw it back to you, get back to your case. And if you want to pick up your interpretation.

Michael Gorin, MD: As is my standard practice, any patient with either high-risk or unfavorable intermediate-risk prostate cancer, I now stage with PSMA PET. This patient underwent a PSMA PET scan. And looking at the imaging, and I’m curious to hear what Dr Saperstein’s thoughts are. This patient underwent a DCFPyL PET scan as is my routine practice for patients with high-risk and unfavorable immediate-risk prostate cancer. On his PET scan, he was found to have 2 small pelvic lymph nodes with SUV [standardized uptake value] values in the range of, max values in the range of approximately 3 to 4. Based on this he was staged as N1 M0. One thing I wish to point out about this, and I’d like to hear Dr Saperstein’s points on this is you could see that these lymph nodes are very close to the ureter. And oftentimes it’s very difficult to discern lymph nodes apart from a segment of ureter that’s clearing the radiotracer. This case was quite difficult to call. I was impressed that our radiologist was able to do it. When I look at the image, one thing that I learned from my colleague, Dr Steve Rowe at Hopkins, is that if you look at your nips and you spin them, you could get a very nice perspective on where the ureter is relative to the lymph nodes and be able to discern them apart. And in this image, what I attempted to do is show you an oblique angle of the patient, where you could see the course of the ureter here, and you could see a high degree of radiotracer uptake in the most distal portion of the ureter. And clearly in front of the ureter is the lymph node with a radiotracer uptake in it.

Neal Shore, MD, FACS: Steven, can I ask you for the benefit of some of our urology and medical oncology colleagues, can you talk about this notion around the measurement of SUV, what it means and how do we best interpret it?

Steven Finkelstein, MD, DABR, FACRO: Yes, the first thing is the higher this standard uptake value, the more you’re feeling like you have a spot that is truly in utterly cancer, right? From a standpoint of a radiation oncologist, I look at this set of images and I’m thinking about how, if I need to treat this patient, am I going to build a radiation plan that makes sense based on the anatomic imaging. Before we would argue for a decade, maybe 2 decades over, do we need to treat just the prostate? Do we need to treat the prostate and mini pelvis? Do we need to treat the full pelvis up to the aortic bifurcation? Those were all defined based on risk factors and equations and things like that. And now we get to the benefit of looking at pictures. And Mike was showing a beautiful picture of this is a patient under consideration for a surgical intervention, under consideration for radiation oncology intervention, where you can treat both the prostate and the lymph nodes up to and above whatever you saw in the imaging. For me, something that is more striking on the imaging one that is felt to be cancer, there’s probably a radiation treatment plan that can encompass that amount of disease.

Transcript edited for clarity.