Practice Updates in Prostate Cancer Imaging - Episode 16
Key opinion leaders review the CONDOR clinical trial studying PSMA PET scans for prostate cancer imaging.
Neal Shore, MD, FACS: Maybe walk through this Mike. This is important for the fact that it was multi-reader and then they had all these different standards of truth for the correct localization rate.
Michael Gorin, MD: The first thing that is apparent from this data is that there was a high rate of disease detection in the setting despite such low PSA [prostate-specific antigen] values, and across readers that was in the range of roughly 60%. Then there was a question of correct localization rate whereby the conventional imaging result is compared, or the confirmatory test result that was performed, is compared back to the PSMA [prostate-specific membrane antigen] PET [positron emission tomography] scan and whether or not those 2 things correlated with one another or was the PSMA uptake say in an area that was not confirmed on the basis of the conventional imaging. Those rates were also quite high, about I’d say on average about 85% of the time, the 2 things had correlated well between both PSMA PET scan and confirmatory test.
Neal Shore, MD, FACS: Mike or Steven or Larry, if you want to comment, but I like these bar graphs, and this is another way of interpreting it. Mike, you want to comment on this? It’s your point, looking on the X axis the various ranges of PSA and seeing the high correct localization rate I this is very impressive data.
Michael Gorin, MD: The most striking thing here is just how often size of disease we are seeing at such low PSA values, which is down here I believe in graph B. And then in graph A, it’s not labeled, but I believe graph A is the correct localization rate and it seems to be high regardless of PSA level. But you do see as PSAs go up, higher overall detection rates. And virtually all patients who had PSAs greater than 5 a site of disease was seen, but in those PSA values it goes down considerably to about 40% but that’s still a pretty large number of patients from whom you learned something about where their site of disease potentially is whereas on the basis of conventional you just had to guess.
Neal Shore, MD, FACS: Here is the FDA indications basically for patients with both newly diagnosed high risk localized disease and for BCR [brachytherapy], but again it’s not just BCR post prostatectomy post radiation, it’s just BCR is a generalization. It’s always good to come in with a concise review of what does a trial truly teach us. Larry, would you like to comment on what does the CONDOR trial teach us regarding patients with BCR?
Lawrence Saperstein, MD: That was a great summary of the trial. Mike touched on all the high points, the disease detection rate, the very high correct localization rate, and what’s compelling is the change in management. And we said that that was roughly 64%, and that’s striking. That’s what it taught me.
Neal Shore, MD, FACS: I agree. It allows us to make and enhance that wanted patient/physician shared decision-making. We could follow up on this case, Mike, and here are the actual scans and the images that were obtained. Can you walk us through that and how this helped you?
Michael Gorin, MD: Recall that this patient’s PSA doubling time was quite slow at 18 months. I had an inkling that this was probably a local recurrence after brachytherapy. However, we see all different outcomes when we order these scans. It’s important to do so but in this patient’s case it did confirm the suspicion where to the extent that the test was able to confirm my suspicion that this was a localized recurrence. I am just looking at the patient straight on. You could see 1 small foci of disease in the prostate itself. This is the bladder, the bladder above it, and then the sites of physiologic updates that we see in all patients who are imaged with it. This is the fused PET and low dose CT scan. You can see a single foci of disease within the prostate itself. You can see all the brachytherapy seeds surrounding it and no other sites of disease whether in the bones or lymph nodes or what have you. This patient I was counseling their treatment options for which include salvage local therapy with ablation, whether it’s HIFU [high-intensity focused ultrasound] or cryotherapy. In those patient who are interested in that I like to also have multiparametric MRI to help plan their treatment and deliver it. I had ordered 1 in this patient’s case and you could see an area of high ADC [apparent diffusion coefficient] values in the exact area where the PSMA update was found.
Neal Shore, MD, FACS: Very nice. This further goes on to how the patient chose a salvage therapy.
Michael Gorin, MD: Yes. I still performed a biopsy, although the PSMA scan is in itself diagnostic. In these early days of PSMA-targeted imaging, it’s best to have tissue. So the patient underwent targeted transperineal biopsy of that PET avid area and was confirmed to have disease recurrence there, and then opted to have hemi-gland cryoablation and did quite well with rather dramatic PSA response.
Neal Shore, MD, FACS: It’s a great case and certainly gave you the information to inform and encourage the patient to consider salvage therapy as opposed to starting on androgen deprivation therapy.
Transcript edited for clarity.