Institutional Experience of Magnetic Resonance Imaging-directed Targeted Transrectal Ultrasound-guided Prostate Biopsy

Objective: To evaluate the efficacy of magnetic resonance imaging (MRI)-directed targeted transrectal ultrasound (TRUS) prostate biopsy in the detection of clinically significant prostate cancer. Methods: The records of patients who underwent MRI-directed targeted TRUS prostate biopsy from August 2013 to December 2014 in a regional hospital in Hong Kong were retrospectively reviewed. The procedure was indicated in patients with persistently elevated prostate-specific antigen (PSA) and at least two consecutive negative random systematic TRUS prostate biopsies. Pre-biopsy MRI localisation was arranged. Multiparametric MRI of the prostate (T2-weighted, diffusion-weighted imaging, apparent diffusion coefficient, dynamic contrast-enhanced imaging, and spectroscopy) was performed and each lesion was mapped to one of 16 sectors of the prostate. Prostate Imaging-Reporting and Data System (PI-RADS) classification was used to score each suspicious lesion. TRUS-guided prostate biopsy was then performed at the sector with PI-RADS score of >= 3. Pathological reports were reviewed and cancer detection rate was calculated. Results: Overall, 27 patients were referred during the study period. Of these patients, seven (25.9%) had positive findings: prostatic acinar adenocarcinoma was identified in six, and high-grade prostatic intra-epithelial neoplasia in one. Among the six patients with adenocarcinoma, three had a Gleason score of >= 7, and three had a score of 6. There was a cancer detection rate of 25.9% in our population with negative random TRUS biopsies and persistently elevated PSA. Conclusion: MRI-directed targeted TRUS prostate biopsy is able to further detect prostate cancer that requires treatment in patients with persistently elevated PSA and repeated negative random TRUS biopsy. The cancer detection rate from our institution is comparable to other reported studies. MRI-directed targeted TRUS prostate biopsy requires no significant extra resources, and may help selected patients in our locality.