851 EARLY DEVELOPMENT OF A MULTIPLEX GIANT MAGNETORESISTIVE NANOSENSOR TO DETECT URINARY MARKERS TO DISCRIMINATE BETWEEN HIGH AND LOW GRADE PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVES: Transperineal mapping template prostate biopsy (TMTPB) has emerged as a diagnostic option for men with a history of negative transrectal guided prostate biopsies. Reported advantages include more precise sampling of the entire prostate gland including the anterior and apical regions. We sought to determine the detection rate and distribution of prostate cancer (PCa) in a group of men with previous negative TRUS biopsy. METHODS: Forty one patients with a history of 1 or more previous negative biopsies underwent TMTPB for primary indication of elevated PSA, elevated PSA velocity, and/or abnormal DRE. Using a transperineal approach, the prostate was systematically biopsied in 26 unique regions guided by a brachytherapy template. Prostate size determined total number of cores. Clinical and biopsy parameters were evaluated as predictors for presence and location of PCa. RESULTS: The overall PCa detection rate was 53.7% (22 of 41). Significant PCa (Gleason score 7) was noted in 14 of 41 (34.1%) patients including 4/41 (9.8%) with high grade PCa (Gleason score 8). There was an average of 4.32 cores positive (S.D. 3.54). 79.8% of positive cores were in the anterior zones vs. only 22.2% were in the posterior zones (p 0.0001). However, the 13 positive cores for Gleason 8 or 9 cancers were evenly distributed: anterior in 7 cores, posterior in 5 cores and periurethral in 1 core. Men had a mean of 2.78 (S.D. 1.46) prior biopsies prior to TMTPB and the number of prior biopsies was not associated with detection. On multivariate analysis for predictors of presence of cancer, only prostate volume was significant (p 0.03). Complications were limited in 8 patients (19.5%): urinary retention (3), hematuria (4) and atrial fibrillation with rapid ventricular rate (1) requiring admission. CONCLUSIONS: TMTPB has a high rate of cancer detection, especially in the anterior zones, even in the setting of multiple previous negative biopsies. A majority of the detected cancers were clinically significant based on Gleason score. Therefore, TMTPB should be considered in any high risk patient with previous negative biopsies.