18F-DCFPyL PET/CT Imaging for Suspected Recurrent Prostate Cancer

Alicia K. Morgans, MD, MPH: As we wrap up this section, let’s talk about exciting advances in imaging allowing personalization and some precise identification of disease. Sandy, what are your thoughts about the data where we can use PSMA [prostate-specific membrane antigen] PET [positron emission tomography] to identify patients who have radiographic evidence of metastatic disease in the biochemical recurrent state in the CONDOR trial, as well as in the high-risk localized state that we saw in the OSPREY trial? What are your thoughts regarding this in your practice? What do you think it means to patients?

Sandy Srinivas, MD: As was said earlier, the ability of this test to pick up disease is somewhat a PSA [prostate-specific antigen] threshold as well. The advantage that this brings compared with our conventional imaging is 2-fold because with a very low level of PSA, we’re able to detect oligometastatic disease. Almost every patient I see in this state has access to PET imaging, and we get them this imaging to understand where this PSA is coming from. Biochemical recurrent disease has become such a big part of our practice to understand what the value of localized radiation would be. In the salvage setting, it’s become a very useful tool for a patient to get radiation.

One thing I wanted to add to the trials is that as a medical oncologist, it’s interesting how the way we conduct clinical studies is so different from diagnostic studying. Reading both of these studies, I was struck because in radiology, they mostly talked about how it changes management. I thought it was interesting that both these trials had such a big focus on, after doing the test, what percentage of patients resulted in a change in management. That was amazing. It was more than 50% of patients for whom there was some change.

The second thing that a lot of patients ask us about is the radiation exposure. Is there more radiation with PET imaging? I found it really interesting that in the OSPREY trial, the authors mentioned that if you look at bone scans and CT scans combined, the PET imaging has a lower radiation dose. It’s important for our patients to understand that about where the value of this test would be. The biggest thing I see in my practice is patients with biochemical recurrence with the lowest PSA who are able to do salvage radiation or metastatic-directed therapy. To me, that’s the biggest value that PSMA brings to the field.

Alicia K. Morgans, MD, MPH: I couldn’t agree more. At this point, if we’re changing management in patients who look clinically localized by our more traditional imaging strategies with PET, that could be challenging because we’re shifting their stage, or that stage migration. Those patients may have a better outcome from a metastatic disease standpoint, but they may have really benefited from whatever we were going to do if we consider them still localized. There are studies that are still trying to sort out how we should best address that, whether it’s SABR [stereotactic ablative body radiotherapy] or something that we would use for patients who would need metastasis-directed therapy in that early stage of new diagnosis or something else.

But in the biochemical recurrent state, it’s all in clinical trials. At least I feel there’s a little more rationale or a little more gray data. We can make some changes in management and not necessarily find ourselves in no man’s land. In any event, this is an area of active investigation. We’re so excited to see where it goes. This personalization is something that’s truly taking off, so thank you—all 3 of you—for talking through it.

Transcript edited for clarity.