Optimal Number of Systematic Biopsy Cores Used in Magnetic Resonance Imaging/Transrectal Ultrasound Fusion Targeted Prostate Biopsy

[Background] In recent years, the effectiveness of magnetic resonance imaging (MRI)-ultrasound fusion targeted biopsy (MRF-TB) has been widely reported. In this study, we assessed the effect of reduction of the number of systematic biopsy (SB) cores on the cancer detection rate (CDR). [Methods] Patients with a high prostate-specific antigen (PSA) level underwent prostate MRI. The Prostate Imaging-Reporting and Data System version 2 (PI-RADS) was then used to rate the lesions. The inclusion criteria were as follows: (1) PSA level between 4.0 and 30.0 ng/mL and (2) patients with one or more lesions on MRI and a PI-RADS score of 3 or more. All enrolled patients were SB naïve or had a history of one or more prior negative SBs. A total of 104 Japanese met this selection criterion. We have traditionally performed 14-core SB following the MRF-TB. In this study, the CDRs of 10-core SB methods, excluding biopsy results at the center of the base and mid-level on both sides, were compared with those of the conventional biopsy method. [Results] We compared CDRs of the 14-core and 10-core SBs used in combination. The overall CDR was 55.8% for the former and 55.8% for the latter, thereby indicating that there was no significant difference (P = 1.00) between the two. In addition, the CDRs of csPCa were 51.9% for the former and 51.1% for the latter, which indicated that there was no significant difference (P = 0.317). [Conclusion] There was no significant difference in the CDR when the number of SB cores to be used in combination was 14 and 10.