DIAGNOSTIC ACCURACY OF GALLIUM-68 PROSTATE-SPECIFIC MEMBRANE ANTIGEN POSITRON EMISSION TOMOGRAPHY/ COMPUTERIZED TOMOGRAPHY IN RECURRENT PROSTATE CANCER PATIENTS: A PROSPECTIVE COHORT STUDY

Introduction: Positron emission tomography (PET)/computed tomography (CT) with 68Ga-labeled prostate-specific membrane antigen ligand (68Ga-PSMA) may represent the most promising alternative to multiparametric magnetic resonance imaging (mpMRI) for prostate cancer (PCa) diagnosis. Aim: We evaluate the specificity, sensitivity, diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) in PCa of 68Ga-PSMA PET/CT for local and lymph node (LN) staging disease with a biochemical recurrence (BCR). Methods: A prospective cohort study of consecutive patients with BCR who underwent 68Ga-PSMA PET/CT and mpMRI followed by a RP or RT was performed between November 2018 to December 2021. Standard clinical parameters were collected. Results: In total, 120 men were included in this analysis (median age 70.5 years, median PSA 3.6 ng/ml). Of these 120 men, 95 patients (79.2%) had a biopsy with a GS ≥ 7, being classified as clinically significant intermediate- and high-risk for PCa. In addition, 72 (60.0%) had previously undergone mpMRI, of which PCa was detected in 56 (80.0%) men. Finally, 98 (81.7%) men had PCa detected by PET/CT (SUVmax ≥ 2.5). PET/CT results for patients previously undergone to mpMRI to obtain an overall accuracy of 73.6%, with a sensitivity of 86.6% and a specificity of 8.3%. The PPV obtained was 82.5% and the NPV was 11.1%. However, when comparing only patients who had a clinically significant PCa biopsy result (GS ≥ 7), PET/CT was able to detect PCa in nine (16.1%) patients that mpMRI had not detected. Conclusion: 68Ga-PSMA PET/CT is highly accurate and sensitive for index lesion detection when compared to mpMRI for local and LN staging of recurrent PCa. Data here suggest 68Ga-PSMA PET/CT to be the standard of care for the staging of high-risk PCa patients.