title: Inability of shear-wave elastography to distinguish malignant from benign prostate tissue - a comparison of biopsy, whole-mount sectioning and shear-wave elastography.
abstract: OBJECTIVE
  This study was designed to assess the possible usefulness of shear-wave elastography in differentiating between benign and malignant tissue in prostate neoplasia.
  
  
  METHODS
  A total of 120 prostate tissue samples were obtained from 10 patients treated by radical prostatectomy and investigated pre-operatively by ultrasound elastography followed by directed biopsy. After resection, whole-mount sectioning and histological examination was performed. The predictions based on shear-wave elastography were compared with biopsy and histological results.
  
  
  RESULTS
  The comparison between the results of shear-wave elastography and those of biopsy was performed by receiver operating characteristic analysis, which suggested an optimum cut-off tissue elasticity value of 50 kPa, in agreement with earlier studies aimed at distinguishing between benign and malignant tissue. However, the diagnostic selectivity (and thus the diagnostic power) was poor (area under the curve 0.527, which hardly differs from the value of 0.500 that would correspond to a complete lack of predictive power); furthermore, application of this cut-off value to the samples led to a sensitivity of only 74% and a specificity of only 43%. An analogous comparison between the results of shear-wave elastography and those of whole-mount histology, which itself is more reliable than biopsy, gave an even poorer diagnostic selectivity (sensitivity of 62%, specificity of 35%). Meaningful association with Gleason score was not found for D'Amico risk groups (p= 0.35).
  
  
  CONCLUSIONS
  The (negative) findings of this investigation add to the dissonance among results of studies investigating the possible value of shear-wave elastography as a diagnostic tool to identify malignant neoplasia. There is a clear need for further research to elucidate the diversity of study results and to identify the usefulness, if any, of the method in question.
authors.affiliation: Department of Urology and Pediatric Urology, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Porsch
authors.affiliation: Department of Urology and Pediatric Urology, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Görner
authors.affiliation: Department of Urology and Pediatric Urology, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Johann Jakob
authors.initials: JJ
authors.lastname: Wendler
authors.affiliation: Department of Urology and Pediatric Urology, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Uwe-Bernd
authors.initials: UB
authors.lastname: Liehr
authors.affiliation: Institute for Biometrics and Medical Informatics, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Lux
authors.affiliation: Institute of Pathology, Otto-von-Guericke University, Magdeburg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Siedentopf
authors.affiliation: Department of Urology and Pediatric Urology, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Schostak
authors.affiliation: Department of Radiology and Nuclear Medicine, Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany.
authors.forename: Maciej
authors.initials: M
authors.lastname: Pech
keywords: elastography; prostate biopsy; prostate cancer; shear wave; ultrasound