Jitesh Dhingra, MD, FRCEM, on PSMA-PET imaging’s impact on treatment decisions in prostate cancer

In this video, Jitesh Dhingra, MD, FRCEM, discusses the impact of prostate-specific membrane antigen (PSMA)-PET imaging in prostate cancer. Dhingra is an attending nuclear medicine physician at Allegheny Health Network in Pittsburgh, Pennsylvania.

Transcription:

How does PSMA-PET imaging impact treatment decisions for patients with prostate cancer, and can it help guide therapy options?

This is basically another [area where PSMA supersedes other imaging]. As I said earlier, PSMA is prostate-specific membrane antigen. So it is basically targeted to prostate cancer cells. When we are using different modalities, we are trying to look for PSMA expression going up or down, and seeing whether the PSMA expression is going down, does that mean response to treatment? Now, having said that, there are multiple studies done, and I'll just give you a brief summary of how studies are being done is that if, whenever we are using androgen deprivation therapy, which is basically like the first line of treatment for patients with prostate cancer, because whenever the prostate cancer is detected, they get a prostatectomy, they get radiation, and are eventually placed on androgen deprivation therapy. Androgen deprivation therapy is supposedly going to lead to an over expression of PSMA in the first 6 months, which is also known as a flare response. But after 6 months of using the same androgen deprivation therapy, we will start seeing a reduction in PSMA levels. Once we start seeing that reduction in PSMA levels, that basically confirms that our treatment is going in the right direction. But instead, if, even after like, 6 months of using androgen deprivation therapy, the PSMA expression keeps going up, that is basically a time for the oncologist or urologist to say, this is time for me to change treatment, because this treatment doesn't seem to be working at this point of time. That's just for androgen deprivation therapy. Now the second thing that was the utility of Pluvicto. So when we are using radionuclide therapies, which are lutetium-based PSMA therapies, we should expect the PSMA expression to go down every time we treat them. But there are patients where I personally have had a decent amount of patients where we are treating patients with Pluvicto, and there are patients where the PSMA expression keeps going up, so now PSMA expression, if it keeps going up on Pluvicto treatment may be a situation and a discussion for the oncologist, urologist, as well as the nuclear medicine physician, to come to a point where they may think, okay, the PSMA is going up with giving Pluvicto. I should start thinking about stopping treatment or trying to do other diagnostic imaging at this point of time. Now, PSMA expression can also go down during Pluvicto. When it goes down, it is usually considered a reassuring step that the patient is getting treated. But then also, I would also like to introduce here another thing that the urologist and the oncologist should be aware of, which is that PSMA expression coming down on Pluvicto doesn't always mean that the patient is doing well. It could also mean that the patient is undergoing neuroendocrine differentiation of prostate cancer, and that's basically where our imaging modalities of clubbing PSMA paired with CT come into the picture, and we just come to a decision that this patient is not progressing on imaging, PSMA expression is coming down, so this means that the patient is doing well vs PSMA expression is coming down, but the patient is progressing on imaging, so I'm concerned about neuroendocrine differentiation, and I need to do other imaging or tissue relation.

This transcript was AI generated and edited by human editors for clarity.