The role of magnetic resonance image-guided prostate biopsy in stratifying men for risk of extracapsular extension at radical prostatectomy - Abstract

PURPOSE: Magnetic resonance imaging (MRI) detects extracapsular extension (ECE) by prostate cancer (PCa) with excellent specificity, but low sensitivity.

This limits surgical planning, which could be modified to account for focal ECE with image-directed guidance for wider excision. The objective of this study is to evaluate the performance of multiparametric MRI (MP-MRI) for ECE detection and to determine which pre-operative variables predict ECE on final pathology when MP-MRI predicts organ-confined disease.

MATERIALS AND METHODS: From May 2007 to March 2014, 169 patients underwent pre-biopsy MP-MRI, MRI/transrectal ultrasound (MRI/TRUS) fusion-guided biopsy, extended sextant 12-core biopsy, and radical prostatectomy (RP) at our institution. A subset of 116 men had MP-MRIs negative for ECE and were included in the final analysis.

RESULTS: The 116 men with MP-MRIs negative for ECE had a median age of 61 years (IQR 57-66) and median PSA of 5.51 ng/ml (IQR 3.91-9.07). The prevalence of ECE was 23.1% in the overall population. Sensitivity, specificity, positive and negative predictive values of MP-MRI for ECE were 48.7%, 73.9%, 35.9%, and 82.8%, respectively. On multivariate regression analysis, only patient age (p=0.002) and MRI/TRUS fusion-guided biopsy Gleason score (p=0.032) were independent predictors of ECE on final RP pathology.

CONCLUSIONS: Because of the low sensitivity of MP-MRI for ECE, further tools are necessary to stratify men at risk for occult ECE that would otherwise only become apparent on final pathology. MRI/TRUS fusion-guided biopsy Gleason score can help identify which men with PCa have ECE that may not be detectable by imaging.

Written by:
Raskolnikov D, George AK, Rais-Bahrami S, Turkbey B, Siddiqui MM, Shakir NA, Okoro C, Rothwax JT, Walton-Diaz A, Sankineni S, Su D, Stamatakis L, Merino MJ, Choyke PL, Wood BJ, Pinto PA.   Are you the author?
Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; Center for Interventional Oncology, National Cancer Institute & Clinical Center, National Institutes of Health, Bethesda, Maryland.  

Reference: J Urol. 2015 Jan 23. pii: S0022-5347(15)00161-5.
doi: 10.1016/j.juro.2015.01.072

PubMed Abstract
PMID: 25623751 Prostate Cancer Section