Platinum Priority – Prostate Cancer Editorial by XXX on pp. x–y of this issue Detection of Individual Prostate Cancer Foci via Multiparametric Magnetic Resonance Imaging David C. Johnson a,b, *, Steven S. Raman c , Sohrab A. Mirak c , Lorna Kwan b , Amirhossein M. Bajgiran c , William Hsu c , Cleo K. Maehara c , Preeti Ahuja c , Izak Faiena b , Aydin Pooli b , Amirali Salmasi b , Anthony Sisk d , Ely R. Felker c , David S.K. Lu c , Robert E. Reiter b, * a Department of Veterans Affairs/National Clinician Scholars Program, Los Angeles, CA, USA; b Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; c Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; d Department of Pathology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA E U R O P E A N U R O L O G Y X X X ( 2 0 18 ) X X X – X X X ava ilable at www.sciencedirect.com journa l homepage: www.europea nurology.com Article info Article history: Accepted November 10, 2018 Associate Editor: Matthew Cooperberg Keywords: Multifocal Multiparametric magnetic resonance imaging Prostate cancer Radical prostatectomy Whole-mount pathology Abstract Background: Multiparametric magnetic resonance imaging (mpMRI) undoubtedly affects the diagnosis and treatment of localized prostate cancer (CaP). However, clinicians need a better understanding of its accuracy and limitations in detecting individual CaP foci to optimize management. Objective: To determine the per-lesion detection rate for CaP foci by mpMRI and identify predictors of tumor detection. Design, setting, and participants: We carried out a retrospective analysis of a prospectively managed database correlating lesion-specific results from mpMRI co-registered with whole- mount pathology (WMP) prostatectomy specimens from June 2010 to February 2018. Parti- cipants include 588 consecutive patients with biopsy-proven CaP undergoing 3-T mpMRI before radical prostatectomy at a single tertiary institution. Outcome measurements and statistical analysis: We measured mpMRI sensitivity in detect- ing individual CaP and clinically significant (any Gleason score 7) CaP foci and predictors of tumor detection using multivariate analysis. Results and limitations: The final analysis included 1213 pathologically confirmed tumor foci in 588 patients with primarily intermediate- (75%) or high-risk (12%) CaP. mpMRI detected 45% of all lesions (95% confidence interval [CI] 42–47%), including 65% of clinically significant lesions (95% CI 61–69%) and nearly 80% of high-grade tumors. Some 74% and 31% of missed solitary and multifocal tumors, respectively, were clinically significant. The majority of missed lesions were small (61.1% 1 cm); 28.3% were between 1 and 2 cm, and 10.4% were >2 cm. mpMRI missed at least one clinically significant focus in 34% of patients overall, and in 45% of men with multifocal lesions. On multivariate analysis, smaller, low-grade, multifocal, non- index tumors with lower prostate-specific antigen density were more likely to be missed. Limitations include selection bias in a prostatectomy cohort, lack of specificity data, an imperfect co-registration process, and uncertain clinical significance for undetected lesions. Conclusions: mpMRI detects less than half of all and less than two-thirds of clinically significant CaP foci. The moderate per-lesion sensitivity and significant proportion of men with undetected tumor foci demonstrate the current limitations of mpMRI. Patient summary: Magnetic resonance imaging of the prostate before surgical removal for prostate cancer finds less than half of all individual prostate cancer tumors. Large, solitary, aggressive tumors are more likely to be visualized on imaging. Published by Elsevier B.V. on behalf of European Association of Urology. * Corresponding authors. Department of Urology, David Geffen School of Medicine, 300 Stein Plaza, Los Angeles, CA 90095, USA. Tel. +1 310 7947700. E-mail addresses: dcjohnson@mednet.ucla.edu (D.C. Johnson), rreiter@mednet.ucla.edu (R.E. Reiter). EURURO-8147; No. of Pages 9 Please cite this article in press as: Johnson DC, et al. Detection of Individual Prostate Cancer Foci via Multiparametric Magnetic Resonance Imaging. Eur Urol (2018), https://doi.org/10.1016/j.eururo.2018.11.031 https://doi.org/10.1016/j.eururo.2018.11.031 0302-2838/Published by Elsevier B.V. on behalf of European Association of Urology.