The Feasibility of Multiparametric Magnetic Resonance Imaging for Targeted Biopsy Using Novel Navigation Systems to Detect Early Stage Prostate Cancer: The Preliminary Experience

Abstract

The feasibility and diagnostic performance of multiparametric magnetic resonance imaging (mp-MRI) has to be proven further. In this study, we evaluate the role of mp-MRI for targeted biopsy of early stage prostate cancer (PCa). A total 32 consecutive patients with transrectal ultrasonography (TRUS)-guided biopsy-proven PCa meeting low-risk criteria and pursuing active surveillance were selected to undergo mp-MRI 3 Tesla (3T) with endorectal coil. Patients were divided then into three groups based on the method used to target the mp-MRI designated region of interest (ROI): Group 1 underwent TRUS-guided prostate biopsy using an MRI-based coordinate plan (cognitive targeting). Group 2 underwent MRI-targeted TRUS-guided prostate biopsy using MyLabTMTwice, which superimposed the archived MRI images onto the real-time ultrasonography image allowing targeted biopsy of the ROI (fusion targeting). Group 3 included selected patients who had an elevation in prostate-specific antigen levels, or patients followed after radiation therapy (two patients) for suspicious unifocal MRI lesion recurrence. These patients underwent MRI-guided biopsy of the suspicious ROI using the navigation system DynaTRIM. The cancer detection rate in group 1 was 33.3% (3 of 10 patients), while in group 2, it was significantly higher at 46.2%. The sensitivity and specificity for group 1 was 45.5% and 33.3%, vs 61.9% and 20.8% in group 2, respectively. The positive predictive value in group 1 was 50.0% vs 53.8% in group 2 (P=0.04). In group 3, the cancer detection rate was much higher (80%) than in group 2, (P=0.005) although the majority of these patients (7 of 10) had a previously diagnosed prostate cancer on TRUS-guided 12-core biopsy. Our preliminary experience of mp-MRI suggests the detection of early stage prostate cancer with low-risk features yields potential candidates for active surveillance or focal targeted therapy. The MRI-TRUS fusion system increases diagnostic yield compared with cognitive MRI-directed TRUS-guided biopsy.