PSMA Imaging: Integration Into Urologic Oncology

As part of GU Oncology Now’s Round the Wire series on PSMA Imaging, moderator Dr. Neeraj Agarwal and Dr. Jonathan Tward discuss the use of PSMA imaging for radiation oncologists and urologists dealing with localized prostate cancer. Speaking to how PSMA imaging alters the management of the cancer, Dr. Tward highlights how the therapies can be adapted to findings from imaging and how treatment recommendations can accordingly be made.

Dr. Agarwal:

I’m going to ask my colleague, Dr. Tward. So Dr. Tward, how are you looking forward to use PSMA imaging in your practice? So you are a radiation oncologist who sees patients with localized prostate cancer. So let me ask you how radiation oncologist or surgeons are going to be using PSMA imaging in their practices?

Dr. Tward:  

Thank you. There’s a large spectrum of application as far as I’m concerned for either a urologist or radiation oncologist, who primarily deals in the localized prostate cancer setting. And I’ll even kind of extend that out a little bit to the concepts of oligometastatic disease as well, which might fall into the realm of considering localized therapies. Until recently what we’ve done, at least in the United States, is been using PSMA PETs and other of these next generation PET CT scans in the biochemical failure setting. So patients who may have had prior surgery or radiation or surgery plus radiation as very, very early phase tests with PSAs as low as maybe 0.2, let’s say to try to get an inclination as to is the disease still localized in the pelvis or not?

So the majority of our use is in that setting, seeing if it’s just maybe in a post-surgical patient in the prostate fossa realm or lymph nodes or in radiation patients persisting disease in the prostate gland itself and/or lymph nodes or more distantly. And it’s actually altered pretty dramatically over the past few years how radiation oncologists have been dealing with biochemical failure when they order the test. It clearly alters management, mainly because you start to identify whether or not there’s nodal disease, whether or not you start to identify it’s a metastatic disease. So, we’re primarily using it to adapt our therapies to the situation that we are seeing rather than what we used to do prior, which was make our treatment recommendations based on the probabilities of things being involved.

Dr. Agarwal:

So salvage radiation therapy, therapy for oligometastatic disease, any other setting?

Dr. Tward:     

Yes, we are now starting to use it in the upfront setting. There was a randomized trial, the pro PSMA trial, I’m sure Dr. Calais can also speak to that as well that really did kind of a head-to-head comparison in the localized prostate cancer setting of conventional imaging versus PSMA imaging. And first of all, it showed that there was much better sensitivity and specificity at using PSMA, but the general conclusion of that study was that it could potentially, well, it should perhaps replace conventional imaging. I think there’s some debate that remains about should it necessarily replace, but I think in the upfront newly diagnosed setting, it can be very helpful in helping guide therapies. For instance, somebody who you would’ve perhaps thought needed surgery or radiation upfront who might have metastatic disease at this point, you can certainly spare them, maybe some of the morbidity of doing treatments if they happen to have widespread metastasis and get them onto appropriate systemic therapies.