Head-to-head comparison of micro-ultrasound, mpMRI, and PSMA PET/CT with a wholemount histopathology as gold standard in the detection and T staging of prostate cancer.

338 Background: Micro-Ultrasound (MicroUS) is a new imaging modality capable of identifying prostate cancer (PCa). Prior evaluation of MicroUS and multiparametric MRI (MRI) have demonstrated comparable accuracy but are limited by relying on biopsy pathology for ground truth. There are no available studies that comprehensively evaluate the diagnostic accuracy and extraprostatic extension (EPE) of MicroUS, MRI, and PSMA PET/CT (PSMA) against wholemount histopathology (WMHP) as the reference. Methods: Patients with PCa who underwent MicroUS and MRI before radical prostatectomy were included. Among the included patients, a subgroup analysis was performed in patients with a PSMA scan. Imaging scans and WMHP findings were translated into involvement on a standardized 36 sector map. Accuracy in determining the PCa, csPCa (GG≥2) and EPE was assessed using receiver-operating-characteristic curve analysis (AUC). Results: The final analysis included 25 patients, 19 of whom underwent PSMA scan. The lesion-level PCa and csPCa detection rates were 55% and 72%, 57% and 75%, 53% and 70% for Micro-US, MRI and PSMA, respectively (Table). For the sector-level analysis, the AUCs of MRI were higher than that of MicroUS and PSMA in identifying PCa, and csPCa (P&lt;0.05). MicroUS and PSMA had comparable sector-level PCa and csPCa AUCs. The AUCs of MRI and PSMA were higher than MicroUS for sector-level EPE (P&lt;0.05). The AUCs for prediction of patient-level EPE were 0.68, 0.69 and 0.54 for MicroUS, MRI and PSMA, respectively (p = NS). Patient level PCa, csPCa, and for specific pathologic features was similar among imaging modalities. Conclusions: MicroUS showed good reliability in identifying csPCa and patient-level EPE. At the patient level, its performance is comparable to that of MRI. MRI performs better at the sector-level. Diagnostic accuracy and EPE staging for MicroUS, MRI, and PSMA PET/CT. N = 25 MicroUS Multiparametric MRI PSMA PET CT P-Value PCa Sector-Level AUC 0.67 (0.64, 0.71) 0.71 (0.68, 0.75) - 0.03 csPCa Sector-Level AUC 0.69 (0.65, 0.72) 0.74 (0.70, 0.77) - 0.01 EPE Patient-Level AUC 0.68 (0.47, 0.88) 0.69 (0.51, 0.87) - 0.93 EPE Sector Level AUC 0.57 (0.47, 0.67) 0.79 (0.65, 0.93) - &lt;0.01 N = 19 PCa Sector-Level AUC 0.66 (0.61, 0.71) 0.62 (0.57, 0.68) 0.62 (0.57, 0.68) 0.03*, &lt;0.01** csPCa Sector-Level AUC 0.67 (0.63, 0.71) 0.71 (0.67, 0.75) 0.64 (0.60, 0.67) 0.06*, &lt;0.01** EPE Patient-Level AUC 0.69 (0.51, 0.87) 0.72 (0.51, 0.94) 0.54 (0.30, 0.78) 0.32*, 0.28** EPE Sector Level AUC 0.54 (0.45, 0.62) 0.78 (0.63, 0.92) 0.73 (0.58, 0.87) 0.01* , 0.50** Pathologic Feature Detection Rates for MicroUS, mpMRI, and PSMA PET CT MicroUS Multiparametric MRI PSMA PET CT P-Value PCa (%) 55.3 57.4 52.8 0.81 csPCa (%) 72.2 75.0 70.4 0.78 Index Lesion (%) 96.0 92.0 84.2 0.26 Cribiform/IDC (%) 94.1 100 <jats:td colspan="1" row