MP17-08 MRI-FUSION PROSTATE BIOPSY IN FIRST-TIME BIOPSY COHORT YIELDS INCREASED DETECTION OF CLINICALLY SIGNIFICANT PROSTATE CANCER USING A SIMPLIFIED MRI GRADING SCALE

Abstract

INTRODUCTION AND OBJECTIVES: Prostate cancer (PCa) is the most common solid organ malignancy in men and the second leading cause of cancer related death; however, it remains the only tumor diagnosed by a random sampling method. Multiparametric MRI (MP-MRI) has been reported in evaluation of men with a persistently elevated PSA after a negative biopsy (bx) and in active surveillance (AS) cohorts, but its role in initial diagnosis has not been independently reported. We describe cancer detection rates (CDR) with MRI-fusion for first-time prostate bx using a simplified 3-point Likert scale for grading prostatic lesions. METHODS: Consecutive patients had an MRI fusion prostate bx for elevated PSA, abnormal DRE, AS, or prior negative bx with persistently elevated PSA. Regions of interest (ROIs) identified on MRI were assigned increasing cancer suspicion levels using a simplified 3point Likert scale by a team of dedicated pelvic radiologists. The Artemis system was used to create an MRI-US fusion 3D model of the prostate and a single urologist (PS) performed both a 12-core transrectal systematic bx as well as a targeted bx of any ROI. RESULTS: A total of 191 patients underwent MRI and fusion bx between 12/2012 and 8/2014. For the entire cohort, overall CDR for systematic bx was 52.3% and for fusion biopsy was 55.0%. However, the detection rate for clinically significant PCa (Gleason 7 or greater) with systematic bx was 28.7% and that for targeted bx was 43.8% (p1⁄40.02). The first-time prostate bx cohort comprised 73 patients. In this group, overall CDR was 73.9% with cancer detected in 79.6% of patients with ROI as opposed to 33.3% of patients without ROI. Furthermore, in this cohort, the targeted bx CDR was 67.1% and systematic bx CDR was 56.2%. Most importantly, clinically significant cancer was detected in 38/73 (52.1%) patients with 36/64 (56%) detected on targeted bx and 27/73 (37%) detected on systematic bx. Evaluation of cancer suspicion level for each ROI revealed that patients with high suspicion scores had a higher overall CDR (p <0.0001) and higher risk of detecting clinically significant cancer (p1⁄40.0001). CONCLUSIONS: MRI fusion prostate bx using MP-MRI as a first-time bx has a higher overall and clinically significant CDR than systematic bx, and correlates with MP-MRI suspicion level. A simplified Likert grading scale in the hands of experienced radiologists correlates with cancer detection and clinically significant cancer. The high CDR of MRI fusion bx in a first-time cohort may alleviate the need for repeat bx and its associated morbidity.