PSMA PET/CT using PSMA ligands labeled with the long-lived radionuclide zirconium-89 represents a promising novel imaging approach for prostate cancer. Preliminary evidence indicates that 89ZrZr-PSMA PET/CT may enhance the detection of tumor lesions in patients with biochemical recurrence (BCR). This study aims to evaluate the positivity rate and feasibility of 89ZrZr-PSMA imaging in patients with very low PSA levels (≤ 0.2 ng/mL). Sixty-five patients with BCR and PSA levels ≤ 0.2 ng/mL undergoing 89ZrZr-PSMA PET/CT were analyzed. The mean PSA level at imaging was 0.14 ± 0.04 ng/mL. PET/CT was performed using a mean injected activity of 129.0 ± 19.3 MBq and an uptake time of 48 h. Positivity rates and potential predictors of scan positivity, including PSA level, PSA doubling time, and initial Gleason score, were evaluated. 89ZrZr-PSMA PET/CT achieved a high overall positivity rate of 72.3%, with 47 of 65 patients presenting with at least one suspicious lesion. Local recurrence was detected in 25 patients, while lymph node and bone metastases were observed in 29 and 4 patients, respectively. Patients with a Gleason score ≥ 8 exhibited a higher positivity rate than those with lower scores (p = 0.047). In patients with BCR and PSA levels ≤ 0.2 ng/mL, 89ZrZr-PSMA PET/CT yielded a 72.3% positivity rate in this single-center cohort of 65 individuals. This notable sensitivity at minimal PSA concentrations may enable early identification of recurrent disease and facilitate individualized targeted therapy.
Speicher et al. (2026) studied this question.