MP36-03\u2003TRANSPERINEAL VS. TRANSRECTAL MRI-US FUSION FOR PROSTATE CANCER DETECTION – A PROSPECTIVE RANDOMIZED STUDY.

Abstract

INTRODUCTION AND OBJECTIVES: MRI-US fusion biopsies can be performed in a transrectal or transperineal approach. In both approaches software alignment between MRI and US derived prostate 3D models are used to direct biopsy needle. Prospective comparative evidence between fusion done transrectaly and transperinealy is limited. METHODS: This was a non-inferiority randomized trial, comparing prostate-cancer detection rate between transperineal and transrectal MRI-US fusion targeted fusion biopsies. For each subject, the index lesion was sampled 4-6 times in both approaches. Subjects were randomized to select which approach will be taken first. Systematic cores were taken in the transperineal approach. All biopsies were done under general anesthesia using Navigo fusion software. Non-inferiority margin for prostate cancer detection was set at 10%. We used mathematical models to test the MRI and US 3D models fit in the transrectal and transperineal approach. RESULTS: Seventy-six patients were randomized. Median age was 68.2 (IQR 64.2-72.2). Median PSA was 8.88 (IQR 6.18-12.2). Prostate-cancer was detected in 45 patients (59%), 21 had a Gleason score 7 or above (47%). Prostate cancer was detected in the index lesion in the transperineal approach in 44 (58%) compared to only 33 (44%) in the transrectal approach. Absolute difference for prostate-cancer diagnosis was 14% (CI90% 27-1.3%) in favor of the transperinal approach p=0.037. Transperinal biopsies were non-inferior to transrectal biopsies and the 90% confidence interval indicated the superiority of transperineal fusion over transrectal biopsies. Further assessment demonstrated that the differences between the two approaches depend on tumor location. Trans perineal biopsies were superior to transrectal in detecting cancer in the apex (47% vs. 31% p=0.043) and anterior (54% vs 31% p=0.04). Moreover, in the mathematical models we found a significant difference in the core length sampled within the index lesion. The median length in apical lesions was 26mm in transperineal compared to 15mm in the transrectal (p=0.04). In anterior lesions transperineal core length was 36mm compared to 14mm transrectal (p=0.001). No differences were found in other locations. CONCLUSIONS: Transperineal fusion biopsies were found to be superior to transrectal fusion biopsies. This difference is most pronounced in the apex or anteriorly. Source of Funding: none