Value of Increasing Biopsy Cores per Target with Cognitive MRI-targeted Transrectal US Prostate Biopsy

Purpose: To determine the increase in clinically significant cancer detection in the prostate with increasing number of core samples obtained by using cognitive MRI-targeted transrectal US biopsy. Materials and Methods: This retrospective cross-sectional study included 330 consecutive patients (mean age, 64.3 years; range, 42-84 years) who underwent multiparametric prostate MRI from March 2012 to July 2017 and had an index lesion that subsequently underwent cognitive MRI-targeted biopsy using transrectal US with at least five core samples (which were sequentially labeled) per lesion. The detection rate of clinically significant cancer was calculated on sequential biopsy cores, comparing the first core alone versus three cores versus five cores per target. Clinically significant cancer was defined as International Society of Urological Pathology Grade Group 2 or higher. Results: Increasing the number of biopsy core samples from one to three per target and from three to five per target increased the detection rate of clinically significant cancer by 6.4% (21 of 330) and 2.4% (eight of 330), respectively. The target yield for clinically significant cancer was 26% (87 of 330), 33% (108 of 330), and 35% (116 of 330) for one, three, and five cores, respectively. Subgroup analysis showed no significant difference in upgrade rates as a function of multiparametric MRI lesion size (P = .53-.59) or location (P = .28-.89). Conclusion: More clinically significant prostate cancers are detected when increasing the number of core biopsy samples per index lesion from one to three and from three to five (6.4% and 2.4%, respectively) when performing cognitive MRI-targeted transrectal US biopsy. (C) RSNA, 2019