Optimal Number of Systematic Biopsy Cores used for Magnetic Resonance Imaging/Transrectal Ultrasound Fusion Targeted 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: : MRI was performed for patients with high prostate-specific antigen (PSA) levels, and the PI–RADS TM (Prostate Imaging-Reporting and Data System version 2) was used to rate the lesions. Patient selection criteria were to satisfy both of the following conditions: ①PSA level between 4.0 ng/ml and 30.0 ng/ml ②Patients having one or more MRI lesions with a PI–RADS score of 3 or more. 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 14-core and 10-core SBs used in combination. The overall CDR was 55.8% for the former and 55.8% for the latter, indicating no significant difference (p = 1.00). In addition, the CDRs of csPCa were 51.9% for the former and 51.1% for the latter, indicating no significant difference (p = 0.317). Conclusion: Even a 10-core SB used in combination with MRF-TB yields a good CDR. Reducing the number of biopsy cores leads to lower patient burden and lower testing costs.