In a study of 207 patients with a median age of 62 years who underwent 68Ga-PSMA PET/CT, investigators found that PSA levels and time to BCR at the time of PSMA PET/CT affect the probability of positive findings at PSMA PET.
Among men with early recurrence or PSA persistence after RP, the study showed that PSMA PET should be recommended even at low PSA levels given its high diagnostic value, according to investigators. The opposite may be true for patients with late BCR, who may not benefit from the addition of a PET PSMA scan. These patients should be counseled carefully based on PSA levels
The researchers stratified patients according to time to BCR (12 months or less [early BCR] or PSA persistence vs more than 12 months [late BCR]) and analyzed the association between the PSA level at PSMA PET/CT and the probability of positive findings. The median PSA value at PSMA PET/CT was 1.0 ng/mL. Overall, 80 men (38%) experienced early BCR or PSA persistence after RP.
On multivariable analysis, higher PSA and early vs late BCR at PSMA PET were significantly associated with approximately 2.2- and 2.6-fold increased odds of positive results, respectively.
Among patients with early BCR, the probability of positive PSMA PET results was high even at low PSA levels and progressively increased with higher PSA level, the investigators reported. The rates of positive findings ranged from 63% to 93%. Conversely, in patients with late BCR, the probability of positive findings was lower than 40% for PSA values less than 0.5 ng/mL
Reference
Robesti D, Mazzone E, Gandaglia G, et al. Optimizing timing and indications for 68Ga-PSMA PET/CT in patients with biochemical recurrent prostate cancer after radical prostatectomy. Presented at: EAU 2022, July 1-4, 2022, Amsterdam, The Netherlands. Abstract: A0190.