Use of PSMA PET Scans in Advanced Prostate Cancer

Neal Shore, MD: When looking at PSMA [prostate-specific membrane antigen] as a PET [positron emission tomography], as that radiotracer, we have 2 very exciting applications that have different approvals throughout the world. In the United States, we have the approval of Gallium 68 PSMA-11 PET at 2 centers in California, and most recently in May, the FDA approved 18F-DCFPyL, or PYLARIFY, as another PSMA PET tracer. Our colleagues in Germany and Australia have had these for quite some time, and there are areas in Northern Europe and in Latin America that have had the ability to use PSMA PET.

Historically, based on the assessments from Prostate Cancer Clinical Trials Working Group [PCWG] 1, 2, and 3, we’ve used conventional imaging in our global, randomized prospective trials when evaluating disease assessment baseline, and also progression when interrogating a new therapeutic. The PCWG has used—and still to this day—conventional imaging, which is multi-slice CT scan and technetium bone scan. We’ve had other PET technologies over the years, such as sodium fluoride and fluciclovine, which has a lot of utilization in the United States; it’s known as the Axumin scan.

The addition of the PSMA PET scans will create a much more robust ability to identify disease when newly diagnosed. There may be high risk for localized expansion outside the prostate or extension: extra prostatic involvement, nodal involvement, and bone disease involvement that until now we could not evaluate with conventional imaging. Why does this make a difference? It can impact our abilities to have a more informed conversation with patients regarding considerations for active surveillance, immediate active treatment of the prostate, of the primary organ, whether it’s surgical or radiation, as well as possibilities for systemic therapy or just systemic therapy as the ideal therapy. We’re in the learning arena right now. We have to do many more trials to understand how this information of more accurate low-volume disease identification compares with how we’ve done our trials with conventional imaging over the years.

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