Diagnostic Value of Prostate-specific Membrane Antigen Positron Emission Tomography / Magnetic Resonance Imaging in Selected Men with Equivocal Prostate Imaging Reporting and Data System Category 3 Lesion (PANDORA): A Prospective Paired Diagnostic Study

PURPOSE: Equivocal Prostate Imaging Reporting and Data System (PI-RADS) category 3 lesions carry an intermediate risk of clinically significant prostate cancer (csPCa). We evaluated the diagnostic value of prostate-specific membrane antigen positron emission tomography/magnetic resonance imaging (PSMA PET/MRI) with [18F]JK-PSMA-7, performed after diagnostic MRI, in biopsy-eligible men with an equivocal PI-RADS category 3 lesion. We hypothesized that PSMA PET-targeted biopsy would detect more csPCa than MRI-targeted biopsy. MATERIALS AND METHODS: We conducted a single-center prospective paired diagnostic study from November 2023 to February 2026. Biopsy-eligible men with an equivocal PI-RADS category 3 lesion on diagnostic MRI and ≥1 high-risk feature underwent pre-biopsy PSMA PET/MRI, with positivity defined as a PRIMARY score ≥3, followed by transperineal MRI-targeted, PSMA PET-targeted when positive, and systematic biopsy. The primary outcome was the per-patient csPCa detection rate (International Society of Urological Pathology grade group ≥2 with ≥10% Gleason pattern 4) of PSMA PET-targeted vs MRI-targeted biopsy, assessed with the exact McNemar test. RESULTS: Of 83 men assessed, 66 completed PSMA PET/MRI and biopsy. PSMA PET was positive in 21 of 66 (32%). PSMA PET-targeted biopsy detected csPCa in 10 of 66 (15%) vs 4 of 66 (6%) for MRI-targeted biopsy (difference 9%; 95% CI 2%-18%; P = .03). Sensitivity, specificity, and negative predictive value of PSMA PET were 100%, 82%, and 100%. Biopsy would have been avoided in 45 of 66 men (68%) with a negative result, none of whom had csPCa. CONCLUSIONS: In biopsy-eligible men with an equivocal PI-RADS category 3 lesion, PSMA PET-targeted biopsy detected more csPCa than MRI-targeted biopsy. The high negative predictive value suggests that deferral of biopsy after a negative result merits evaluation in larger multicentre studies.