Emerging research suggests that hormone therapy has no significant impact upon the diagnostic efficacy of 18F-piflufolastat PET/CT for detecting recurrent or metastatic prostate cancer.
For the retrospective study, recently published in The Prostate, researchers evaluated the use of 18F-piflufolastat PET/CT (Pylarify, Lantheus) in 93 patients with elevated prostate-specific antigen (PSA) levels and suspected local recurrence or metastasis. The study authors noted that 32 patients in the cohort were taking concomitant hormone therapy (HT).
The researchers found a median sensitivity of 96.4 percent for 18F-piflufolastat PET/CT in patients taking concurrent HT vs. 95.4 percent for those not on HT. While the median positive predictive value (PPV) for 18F-piflufolastat PET/CT was higher in patients with concurrent HT (90 percent vs. 80 percent), the study authors noted no statistically significant difference between the two cohorts.
“Our findings suggest that 18F-piflufolastat PET/CT can be performed in recurrent or metastatic prostate cancer patients, independent of concurrent HT use or its duration,” wrote lead study author Lawrence Saperstein, M.D., who is affiliated with the Department of Radiology and Biomedical Imaging at the Yale School of Medicine, and colleagues.
The study authors also noted no differences with the radiotracer with respect to testosterone levels in the cohort.
Three Key Takeaways
1. Hormone therapy (HT) does not significantly affect diagnostic performance. The study found no statistically significant difference in sensitivity or positive predictive value (PPV) of ¹⁸F-piflufolastat PET/CT between patients receiving HT and those who were not.
2. Testosterone levels (castration status) have minimal impact. Diagnostic efficacy of the PET/CT scan remained consistent regardless of whether testosterone levels were below or above 50 ng/dL, indicating independence from androgen deprivation therapy (ADT) status.
3. High sensitivity and PPV across groups. The PET/CT scan showed high sensitivity (~95%) and PPV (~80–90%) in detecting recurrent or metastatic prostate cancer, suggesting its broad reliability in various clinical scenarios.
For patients with testosterone levels < 50 ng/dL, the researchers found that 18F-piflufolastat PET/CT offered a median sensitivity of 95.3 percent and an 85.3 percent median PPV for recurrent and metastatic PCa. In contrast, the study authors pointed to a 95.2 percent median sensitivity and an 81.3 percent median PPV for patients with testosterone levels > 50 ng/dL.
“While diagnostic performance did not appear to be impacted by (androgen deprivation therapy) ADT status, we also examined whether castration status (testosterone < 50 ng/dL) influenced the sensitivity and/or PPV of 18F-piflufolastat PET/CT in patients with recurrent or metastatic prostate cancer. Like ADT status, castration status did not appear to impact diagnostic performance,” added Saperstein and colleagues.
(Editor’s note: For related content, see “Emerging PET/CT Agent Shows Promise in Detecting PCa Recurrence in Patients with Low PSA Levels,” “What a New Meta-Analysis Reveals About PET/CT Radiotracers for csPCa” and “Study Shows Discordance Between PSMA PET/CT and PSA Response in 47 Percent of Patients Treated for mCRPC.”)
Beyond the retrospective nature of the study, the authors said other limitations included the low number of the cohort receiving concomitant hormone therapy and the subsequent lack of sub-analysis. They also acknowledged variability with prior treatments and the duration of concomitant hormone therapy.
