PSMA Imaging in Oligometastatic Prostate Cancer

Matthew Deek, MD, Department of Radiation Oncology, Rutgers Cancer Institute, New Brunswick, NJ, shares with us how PSMA imaging used in both the STOMP and ORIOLE trials.

Dr. Deek: STOMP used something called choline imaging, so they didn’t use PSMA. So, it’s the same idea, but there’s some slight nuances and differences in terms of the radio tracer that’s used. In ORIOLE, PSMA imaging was used, and the trial was run out of Johns Hopkins. And one of the leaders in PSMA imaging is a faculty member down there. And so that sort of helped us to integrate PSMA imaging early in the ORIOLE trial. And so patients received, actually, both what we call conventional imaging, which would be a CT, and a bone marrow bone scan, but also patients then additionally had this PSMA imaging, which is a more sensitive imaging for picking up areas of prostate cancer.

When it came to actually treating patients, because this was early on when PSMA was being used, we were actually blinded to the PSMA results. So we didn’t actually know what the PSMA showed, but because we had these matched PSMA scans, we were able to do some secondary or exploratory analyses assessing the impact of using PSMA. And interestingly, and sort of unsurprisingly, what you would know in a lot of these patients, you would get the CT scan or the bone scan and you would see a couple of lesions, but then in some individuals, you would see a lot more than when then you looked at the PSMA, which makes sense because it’s a much more sensitive imaging modality. And the really interesting thing that we found from this was that in the patients who, by chance, all of the metastases that showed up in the CT scan or the bone scan also showed up in the PSMA scan, which meant when they were treated, all of the lesions were treated, compared to a patient who maybe had two sites on the bone scan or the CT scan, but had four sites on the PSMA, so only half of their lesions were treated.

There was a large benefit in terms of the patients who had all of their disease treated. And so the idea there would be that there could be a benefit in the future, and this is really the way we’re going to integrate PSMA earlier on, so that we have a better idea of really how much prostate cancer is there, and so that we can target all of it because it seems like that might be beneficial for patients.

View Dr. Deek’s other comments on oligometastatic prostate cancer, including MDT in the ORIOLE and STOMP Trials, High-Risk Mutations, and The Future of Personalized Care.