Diagnostic efficacy of Gallium-68-PSMA PET/CT in 565 patients with biochemical recurrence of prostate cancer

Ziel/Aim:

The purpose of this study was to investigate the diagnostic efficacy of Gallium(Ga)-68-PSMA PET/CT in patients for detecting and localizing recurrent prostate cancer (PC) taking into account prostate-specific antigen (PSA), PSA doubling time (PSAdt) and PSA velocity (PSAvel).

Methodik/Methods:

We retrospectively studied Ga-68-PSMA-11 PET/CT scans of 565 patients with biochemical recurrence of PC who had previously been treated for localized cancer. The detection rates of PSMA PET/CT were correlated with serum PSA levels, PSAdt (in 525 patients) and PSAvel (in 160 patients). Additionally the rates of localized cancer versus distant metastases in relation to these PSA-biomarkers were assessed.

Ergebnisse/Results:

Cancer detection was positively associated with PSA levels. For PSA values of lower than 0.2 ng/ml, the detection rate was 64%. The detection rate was 55% for PSA values of 0.2-< 0.5 ng/ml, 61% for PSA values of 0.5-< 1.0 ng/ml and 74% for PSA values of 1.0-< 2.0 ng/ml. For PSA values of 2.0-< 5.0 ng/ml, the detection rate increased to 83% and reached 95% at PSA values of ≥5.0 ng/ml. No significant association could be found for PSAdt (70%, 72%, and 80% in < 6, 6-< 12, and ≥12 months, respectively). However, detection rates increased with higher PSAvel. At low PSA levels (< 1 ng/ml/y), the detection efficacy of PSAvel was 45% and increased to 97% at PSA > 5 ng/ml/y.

Schlussfolgerungen/Conclusions:

In this large patient cohort, Ga-68-PSMA PET/CT demonstrates a high detection efficacy in patients with biochemical recurrence of PC. Even in patients with very low PSA levels (< 0.2 ng/ml), it reveals a high number of cancer lesions. Ga-68-PSMA ligand PET/CT enables the diagnosis and localization of recurrent disease with implications for clinically disease management, which can help direct further appropriate treatments (localized vs. systemic therapy).