Magnetic resonance imaging-directed biopsy improves the prediction of prostate cancer aggressiveness compared with a 12-core transrectal ultrasound-guided prostate biopsy

The Gleason grading system is a fundamental indicator of the aggressive nature of prostate cancer (PCa). Diffusion-weighted imaging (DWI) and magnetic resonance (MR) spectroscopy (MRS) are methods for the assessment of PCa aggressiveness. The present study was designed to prospectively investigate whether transrectal ultrasound (TRUS)-guided MR imaging (MRI)-directed biopsies (TRUS-MR-Dbs) improve the prediction of PCa aggressiveness in comparison with 12-core TRUS-guided biopsies (TRUS-Gbs). A total of 518 patients underwent pre-biopsy multi-parametric MRI to identify the clinically suspicious PCa regions. TRUS-MR-Dbs were performed on patients with suspected PCa by MRI in addition to TRUS-Gbs. Only patients who underwent radical prostatectomy (RP) were included in the comparative analysis. TRUS-biopsy was directed to those areas within suspicious regions with a minimum apparent diffusion coefficient obtained by DWI or with a maximum (choline + creatine)/citrate ratio obtained by MRS. The highest Gleason grades (HGGs) and the Gleason scores (GSs) of specimens were identified. The biopsies and RP results were evaluated using a McNemar test or χ2 analyses using Fisher' exact tests. MRI results were positive in 254 (49.0%) of the 518 patients. TRUS-MR-Db detected 165/254 (65.0%) cancer cases and TRUS-Gb detected 190/518 (36.7%) cancer cases. Forty patients underwent RP. The TRUS-MR-Dbs method demonstrated a higher concordance rate (CR) with RP (89.6%) than TRUS-Gbs (72.9%, P=0.008) for the overall HGG. The CRs with RP for TRUS-MR-Dbs vs. those for TRUS-Gbs were 100 vs. 85.7% (P=0.5), 87.5 vs. 68.8% (P=0.031) and 50 vs. 50% (P=1) for HGG3, HGG4 and HGG5, respectively. The HGG CRs with RP for DWI-directed biopsies (DWI-Dbs) vs. MRS-directed biopsies (MRS-Dbs) were 77.1 vs. 50.0% (P=0.015) for the overall tumors, 80.0 vs. 40.0% (P=0.003) for peripheral zone tumors and 69.2 vs. 76.9% (P=1) for transition zone tumors. A total of 37 (77.1%) and 25 (52.1%; P=0.007) tumors were assigned accurate GS for TRUS-MR-Dbs and TRUS-Gbs, respectively. The results revealed that TRUS-MR-Dbs improved the prediction of PCa aggressiveness and that DWI-Dbs had a superior performance when compared with MRS-Dbs in the peripheral zone.