The Impact of Magnetic Resonance Imaging on Prediction of Extraprostatic Extension and Prostatectomy Outcome in Patients with Low-, Intermediate- and High-Risk Prostate Cancer: Try to Find a Standard

Abstract

PURPOSE: To investigate the value of multiparametric magnetic resonance imaging (mpMRI) and to predict extracapsular extension (ECE), seminal vesicle (SV) infiltration, and a negative surgical margin (SM) status at radical prostatectomy (RP) for different prostate cancer (PC) risk groups. PATIENTS AND METHODS: In the study, 805 men underwent 3 tesla mpMRI without endorectal coil before MRI/transrectal ultrasonography-fusion guided prostate biopsy. MRIs were analyzed using the prostate imaging reporting and data system. The cohort was classified into risk groups according to National Comprehensive Cancer Network (NCCN) criteria. Of 132 men who subsequently underwent RP, pathologic stage and SM status at RP were used as reference. Retrospectively, we investigated a European Society of Urogenital Radiology (ESUR) score for ECE and SV-infiltration. Statistical analyses included regression analyses, receiver operating characteristics (ROC), and Youden Index to assess an ESUR-score cutoff. RESULTS: Area under the curve in ROC curve analyses was 0.82 for ESUR-ECE score to detect pT(3a)-disease and 0.77 for ESUR-SV score for pT(3b). Using a cutoff of 4 for ECE and of 2 for SV, the positive predictive value of the ECE-score for harboring pT(3) was 50.0%, 90.0%, and 88.8% for the low-, intermediate- and high-risk cohort. Retrospectively, the use of the ESUR-ECE score preoperatively would have changed the initial surgical plan, according to NCCN criteria, in 31.1% of patients. In the high-risk subgroup, 9/35 (25.7%) patients were correctly assessed as not harboring pT(3) by imaging (ECE score <4), and would have allowed secure robot-assisted radical prostatectomy and nerve-sparing surgery (NSS). When T3 suspicion on preoperative MRI would be taken into account, intraoperative frozen-sections (IFS) might avoid positive SM in 12/18 high-risk patients and an oncologic secure NSS in 8/20 intermediate-risk patients. CONCLUSION: Prediction of pT(3) disease is crucial to plan NSS and to achieve negative SM in RP. Standardized ECE scoring on mpMRI is an independent predictor of pT(3) and may help to plan RP with oncologic security, even in high-risk patients. In addition, it allows more accurate selection of a subgroup of patients for systematic and MRI-guided IFS.