The Added Value of Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography to Magnetic Resonance Imaging for Local Staging of Prostate Cancer in Patients Undergoing Radical Prostatectomy

Combined use of prostate-specific membrane antigen positron emission tomography/computed tomography and magnetic resonance imaging (MRI) for local staging of prostate cancer is advised, as this strategy significantly improves detection of extraprostatic extension and seminal vesicle invasion over MRI alone. The role of prostate-specific membrane antigen (PSMA)-based positron emission tomography (PET)/computed tomography (CT) in addition to magnetic resonance imaging (MRI) for local staging of prostate cancer (PC) has been poorly addressed so far. Our aim was to assess the diagnostic accuracy of PSMA PET/CT and MRI, alone and combined, for detection of extraprostatic extension (EPE) and seminal vesicle invasion (SVI) in PC. We conducted a multicenter retrospective study evaluating patients undergoing PSMA PET/CT and MRI before radical prostatectomy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) for detection of EPE and SVI were calculated for MRI and PSMA PET/CT alone and combined. We included 550 patients, of whom 2%, had low-risk, 43% had intermediate-risk, and 55% had high-risk PC. Overall, 52% of patients had EPE and 21% had SVI at histopathology. Patient-based comparison of MRI versus PSMA PET/CT for detection of EPE revealed sensitivity of 60% versus 41% (p