How Many Targeted Biopsy Cores are Needed for Clinically Significant Prostate Cancer Detection during Transperineal Magnetic Resonance Imaging Ultrasound Fusion Biopsy

PURPOSE To uncover the optimal number of transperineal magnetic resonance imaging ultrasound (MRI/US) fusion targeted biopsy (TB) cores per lesion needed for detection of clinically significant prostate cancer (csPCa). MATERIALS AND METHODS A total of 101 patients with at least 1 lesion with a PI-RADS (Prostate Imaging Reporting and Data System) score of 3 or greater were recruited prospectively. At least 4 transperineal MRI/US fusion TB cores per lesion were performed, followed by systematic biopsy (SB). The Kappa test was used to evaluate the consistency of csPCa detection rate (CDR) between different TB cores and ≥4 cores which was regarded as reference standard. RESULTS In the total cohort of 101 patients, 49 (48.5%), 55 (54.5%), and 57 (56.4 %) were detected with csPCa by SB, TB, or TB+SB, respectively. As for the total of 161 lesions, the CDR based upon 1, 2, 3, or ≥4 TB cores was made in 27.3%, 32.9%, 37.3% and 39.1%, respectively. Three cores showed great consistency with ≥4 cores in CDR (Kappa coefficient of 0.961, P<0.001) with a sensitivity of 95.2% (95% confidence interval 85.8-98.8%), and only miss 3 lesions harboring csPCa. The similar results were obtained in cases with PI-RADS 3 or 4 or maximal diameter of < 1.5 cm. CONCLUSIONS This study demonstrated that three TBs per lesion were suitable during transperineal MRI/US fusion biopsy, especially for lesions of PI-RADS 3 or 4 or small lesions (maximal diameter < 1.5 cm), which may help to tailor targeted prostate biopsy procedures.