LAUSR

134Background: The optimal number of MRI-US fusion biopsy cores to adequately sample regions of interest (ROI) remains unknown. To better understand the optimal approach to lesion targeting, we aimed to examine the cancer detection rate based on sequential number of cores obtained. Methods: Of 744 patients undergoing MRI-US fusion biopsy between 2012 and 2016 at our institution, we identified 628 men with targets on multi-parametric MRI (mpMRI) who underwent targeted and systematic fusion biopsy using the Artemis platform for clinical suspicion (n=465) or known history of PCa (n=163). mpMRI studies were reviewed by genitourinary radiologists using a 3-tiered Likert scale and PI-RADS classification schema. Biopsy was performed by two urologists performing a high volume of fusion biopsies (PS and RD). Cores were taken sequentially from each ROI with an even distribution. The primary outcome was the proportion of high-grade (Gleason ≥3+4) cancers missed on a 2-core lesion biopsy. Results: We biopsied 1,233 R...