Multiparametric magnetic resonance imaging identifies significant apical prostate cancers.

OBJECTIVE: To determine if multiparametric (mp) magnetic resonance imaging (MRI) can identify significant apical disease, thereby informing decisions regarding preservation of the membranous urethra. MATERIALS AND METHODS: Men undergoing radical prostatectomy (RP) between January 2012 and June 2016, who underwent a 12-core transrectal ultrasonography-guided systematic biopsy (SB), preoperative 3-Tesla MRI, and sectioning of the prostate specimen with tumour foci mapping, were extracted from a single surgeon's prospective longitudinal outcomes database. Apical SB and mpMRI lesion results were compared with regard to their ability to predict aggressive tumours in the prostatic apex (PA), defined as prostate cancer grade group >1. RESULTS: Of the 100 men who met the eligibility criteria, 43 (43%) exhibited aggressive prostate cancer in the distal 5 mm of the apex. A Likert score >2 in the apical one-third of the prostate was found to be more reliable than any cancer found on apical SB at detecting aggressive cancer in the apex. On multivariate regression analysis, which included Likert score in the apex, age, prostate-specific antigen (PSA) level, prostate size and presence of any cancer on apical biopsy, only Likert score (P = 0.005) and PSA level (P = 0.025) were significant and independent predictors of aggressive cancer in the distal apex. CONCLUSION: The results of the study showed that MRI was superior to SB at identifying aggressive prostate cancer within the distal PA and may be useful for planning the extent of apical preservation during RP.