Molecular Imaging in Focus: Comparative PSMA PET Study Offers Insights for Men with Recurrent PCa and Low PSA Values

For men with prostate-specific antigen (PSA) values < 0.5 ng/mL and biochemical recurrence (BCR) of prostate cancer (PCa), new intra-patient comparative research suggests that ¹⁸F-flotufolastat provided consistently higher detection rates (DRs) than ¹⁸F-piflufolastat.

For the phase 4 trial, which was recently presented at the American Society for Radiation Oncology (ASTRO) conference, researchers compared the use of ¹⁸F-flotufolastat (Posluma, Blue Earth Diagnostics) and ¹⁸F-piflufolastat (Pylarify, Lantheus) in 55 men with a median PSA of 0.28 ng/mL).¹

Does ¹⁸F-Flotufolastat Offer Consistent Detection of PCa with Different Clinical Factors?

While the study was only powered to evaluate the urinary excretion of the two PSMA PET agents and affirmed that it was lower with ¹⁸F-flotufolastat, the researchers examined the potential impact of different clinical factors upon PCa detection with these PSMA PET agents.

Overall, those in the ¹⁸F-flotufolastat group had a higher patient-level DR in comparison to those who had ¹⁸F-piflufolastat (45 percent vs. 27 percent), according to the study authors. For those with BCR occurring less than five years after radical prostatectomy (RP), the researchers noted a 50 percent DR for ¹⁸F-flotufolastat in contrast to 31 percent for ¹⁸F-piflufolastat. In comparison to ¹⁸F-piflufolastat, ¹⁸F-flotufolastat also offered consistently higher DR at PSA levels as low as < 0.1 ng/mL and more than double the DR among patients with an initial NO diagnosis (42 percent vs. 21 percent), according to the researchers.¹

‘Quite Striking’ Differences Between PSMA PET Agents in Detecting Prostate Cancer

While emphasizing that the increased DR findings with ¹⁸F-flotufolastat were not statistically significant in this study, lead study author Jack Andrews, MD, maintained in a recent episode of our Molecular Imaging in Focus series that some cases were “quite striking” in the differences between ¹⁸F-flotufolastat and ¹⁸F-piflufolastat.

“ … There are a few patients (in whom) you cannot see disease at the vesicourethral anastomosis with the ¹⁸F-piflufolastat scan, but on the ¹⁸F-flotufolastat scan, it's very obvious, and I think that's really what the hope is. We're hoping to make this where radiologists and nuclear medicine doctors who are reading these scans can see it from a mile away to make their job easier to help give us a higher level of personalization for our treatment decisions,” noted Dr. Andrews, a urologic oncologist and assistant professor of urology at the Mayo Clinic in Rochester, Minn.

Can PSMA PET Play A Role in Reducing Unnecessary Salvage Radiotherapy?

Overall, Dr. Andrews emphasized that PSMA PET can play a key role in facilitating appropriate treatment pathways and reducing salvage radiotherapy in patients with no disease in the pelvis.

“My hope is that as we improve with our imaging and our other biomarkers, we can really help select those men who can avoid salvage pelvic radiation and can get more targeted, specific metastasis-directed therapy,” explained Dr. Andrews. “ … I'm really excited to see how that evolves because ultimately, we want to get the right therapy to the right patient. We want to intensify therapy for the correct patient and de-intensify the therapy to avoid some side effects for the patients who don't need more intensified therapy. I think PSMA PET is a really valuable component of that personalization.”

Reference

1. Andrews JR, Sykes J, Cohen T. Impact of clinical factors on ¹⁸F-piflufolastat and ¹⁸F-flotufolastat detection rates in patients with recurrent prostate cancer post-prostatectomy: results from an intra-patient head-to-head study. Presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting, September 26-September 30, 2026, Boston. Available at: https://www.astro.org/meetings-and-education/micro-sites/2026/annual-meeting .