The predictive value of endorectal 3-Tesla multiparametric MRI for extraprostatic extension in low-, intermediate and high-risk prostate cancer patients

D.M. Somford, E.H. Hamoen, J.J. Fütterer, J.P. van Basten, C.A.H. van de Kaa, W. Vreuls, I.M. van Oort, H. Vergunst, L.A. Kiemeney, J.O. Barentsz and J.A. Witjes

Journal of Urology 2013;190:1728-1734

DOI PMID

Abstract

PURPOSE: We aimed to determine the positive and negative predictive values of multiparametric MRI (MP-MRI) for extraprostatic extension (EPE) at radical prostatectomy (RP) for different prostate cancer (PCa) risk groups. MATERIALS AND METHODS: We evaluated a cohort of 183 patients that underwent 3 Tesla (3-T) MP-MRI, including T2-weighted, diffusion-weighted MR Imaging (DWI) and dynamic contrast-enhanced (DCE) sequences, with an endorectal coil (ERC) before RP, pathological stage at RP was used as standard reference for EPE. The cohort was classified into low-, intermediate and high-risk groups according to the d'Amico criteria. We recorded prevalence of EPE at RP and determined sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MP-MRI for EPE in each group. Uni- and multivariable analyses were performed to identify predictors of EPE at RP. RESULTS: Overall prevalence of EPE at RP was 49.7% ranging from 24.7-77.1% between low- and high-risk categories. Overall staging accuracy of MP-MRI for EPE was 73.8 with sensitivity, specificity, PPV and NPV of 58.2 89.1 84.1% and 68.3 respectively. PPV of MP-MRI for EPE was best in the high-risk cohort with 88.8 NPV was highest in the low-risk cohort with 87.7 With an odds ratio (OR) of 10.3 MP-MRI is by far the best pre-operative predictor of EPE at RP. CONCLUSIONS: For adequate patient counselling, knowledge of predictive values of MP-MRI for EPE is of utmost importance. High NPV, important for decisions on nerve-sparing strategies at RP, is only reached in low-risk subjects.