Eric Li, MD, on PSMA-PET imaging in men with low PSA levels

In this video, Eric Li, MD, describes the background and notable findings from the Journal of Urology paper “Clinical Factors Associated with Suspicious 18F-DCFPyL PSMA PET Activity in Patients Initially Managed with Radical Prostatectomy including PSA <0.5 ng/mL.” Li is a urology resident at Northwestern University Feinberg School of Medicine in Chicago, Illinois.

Transcription:

Please describe the background for this study.

We know that prostate cancer is the most common malignancy in men, and radical prostatectomy remains one of the primary treatments for patients with localized prostate cancer. In the US, we do about 90,000 radical prostatectomies every year. And as you were mentioning, prostate specific membrane antigen or PSMA PET has emerged as a superior modality, both for initial diagnosis before we decide what treatment we want to pursue, but also at the time of recurrence. So our paper focused on patients who got radical prostatectomy as their primary treatment for prostate cancer. Currently, there are limited data on low PSA values. Most of the trials only included patients above 0.2, and so we looked at PSAs below 0.2 and also PSAs below 0.5 just because there hasn't really been a lot of work done in that area.

What were some of the notable findings?

As I mentioned, this was a retrospective cohort across the Northwestern system across our 11 hospitals for patients initially managed with radical prostatectomy. We had about 415 patients, and surprisingly, over half of them actually had a PSA value of below 0.5. We found that almost half of them had suspicious findings as defined by the radiologist, but also that the positivity rate for PSAs below 0.5 were around 35%, which is much higher than we thought it would be. We looked at what factors were associated with the suspicious PSMA activity, and for the cohort that was below PSA 0.5, we found that prior postoperative radiation was associated with PSMA positive findings. Now, when you look at the entire cohort, we found that age, Gleason grade at radical prostatectomy, and PSA at PSMA-PET were all associated as well.

And then we did a series of sensitivity analyses looking at various risk stratification tools such as PSA doubling time. We used a nomogram called the CAPRA-S, which has been previously published on, as well as the EAU risk stratification that's also been previously published. Those were all associated with suspicious PSMA activity. The part that really excites me is, well, how does this change patient management? And we looked at, of those with suspicion for metastatic disease, how many of those people received metastasis-directed therapy, and we found that about 40% in the overall cohort and about half of patients with PSA below 0.5 actually received metastasis-directed therapy where it changed the radiation plan and radiation field. So to me, that's really the most exciting part about this work.

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