Rainjade Chung: Thank you for having me.
Neeraj Agarwal: Dr. Chung, please tell me more about the presentation you did at the 2026 annual AUA meeting in Washington DC, where we are sitting. We really loved your presentation. Would you please tell us more about the overall topic and then we can move to discuss the more nuanced aspects of the abstract?
Rainjade Chung: So as you know, PSMA PET is an increasingly used imaging modality to detect either recurrent or metastatic prostate cancer. And we love to use it because it has high sensitivity. However, we don't have robust data in its use for detecting locally recurrent prostate cancer after radiation therapy.
Neeraj Agarwal: That's a great topic because the way we always look at PSMA PET scan in localized prostate cancer setting, pretty much we are focused on distant metastasis, distant recurrences. I don't think there are data on the use of PSMA PET scan in predicting locally recurrence disease. So this is very novel research, I must tell you that. So tell us more about what kind of research was that, what was sample size, the primary endpoint.
Rainjade Chung: So this was a single institution retrospective study. We included patients who received radiation therapy as their primary treatment at our institution who then had a biochemical recurrence and a subsequent PSMA PET scan. And if there was an avid lesion that was then biopsied. It was a cognitive fusion biopsy, and this was all done at our institution. And so we have histopathologic confirmation of these avid lesions. And we found that of the 25 patients that we identified, 19 of them were positive for prostate cancer, meaning that one in four of the PET avid lesions were false positives.
Neeraj Agarwal: Of these patients who got PSMA PET scan and were shown to have a lesion in the local area in the pelvis, on in four did not have disease on the biopsy. So three out of four had disease on the biopsy, on recurrent prostate cancer in the biopsy, but one did not. And potentially it looks like, based on your results, these patients can avoid salvage radiation therapy or salvage therapies.
Rainjade Chung: Right. Our takeaway from this data is that PSMA PET should not be used alone in deciding whether to proceed with salvage treatment and that it should be histopathologically confirmed. And this way we can reduce patient overtreatment and the morbidity associated with salvage therapy.
Neeraj Agarwal: So that's one clear cut message from this. What is the role of MRI in this setting? Just for my knowledge, just for our viewers today. If you see something on the PSMA PET scan, and say the lesion is not biopsiable, you cannot biopsy, you cannot access the lesion, or even if you can access, any role of MRI in this setting?
Rainjade Chung: Ideally, you can have the MRI for enhanced imaging in conjunction with the PSMA PET, or sometimes patients are unable to get an MRI or have hip replacements or fiducial markers that result in poor image quality. So sometimes you are in this very setting where all you have is your PSMA PET scan. But there is data showing that PSMA PET in conjunction with MRI together they do have a high predictive value for detecting recurrence.
Neeraj Agarwal: So for practice perspective, if I see someone to have rising PSA level after definitive therapy, in this context is radiation, but even after any definitive therapy, the ideal test may be the combination of PSMA PET scan plus an MRI to improve the sensitivity as well as specificity.
Rainjade Chung: Exactly.
Neeraj Agarwal: So the message here is PSMA PET scan may show false positive lesions in the pelvis in one out of four patients.
Rainjade Chung: Exactly.
Neeraj Agarwal: And biopsy should be the gold standard before we pursue salvage therapies in these patients. Is that correct?
Rainjade Chung: Correct.
Neeraj Agarwal: Well, congratulations, Dr. Chung, for presenting your data at the AUA meeting in Washington DC. And we look forward to hearing more from your further research down the line.
Rainjade Chung: Thank you.