title: Can multiparametric magnetic resonance imaging predict upgrading of transrectal ultrasound biopsy results at more definitive histology?
abstract: OBJECTIVE
  To determine whether multiparametric magnetic resonance imaging (mp-MRI) has a role in reducing the uncertainty in risk stratification by transrectal ultrasound (TRUS) biopsy, using histology at transperineal template-guided prostate mapping (TPM) biopsy as the reference test.
  
  
  METHODS
  Overall, 194 patients underwent TRUS biopsy, who were followed up in less than 18 months by means of (a) mp-MRI with pelvic phased array using T2-weighted, diffusion-weighted and dynamic contrast-enhanced sequences and (b) TPM biopsy. Of those patients, low risk on TRUS biopsy was defined in 4 different ways--(a) definition 1: Gleason 3+3 (any cancer core length) (n = 137), (b) definition 2: maximum cancer core length (MCCL)<50% (any Gleason score) (n = 62), (c) definition 3: Gleason 3+3 and MCCL<50% (n = 52), and (d) definition 4: Gleason 3+3, MCCL<50%, prostate-specific antigen level<10 ng/ml, and<50% positive cores (n = 28). Mp-MRI was scored for the likelihood of cancer from 1 (cancer very unlikely) to 5 (cancer very likely). Binary logistic regression analysis was performed to evaluate the association between MRI scores and TPM histology.
  
  
  RESULTS
  Median prostate-specific antigen level was 7 ng/ml (range: 0.9-29), median time between TRUS biopsy and mp-MRI was 120 days (range: 41-480), and median time between mp-MRI and TPM biopsy was 60 days (range: 1-420). A median of 48 cores (range: 20-118) were taken at TPM biopsy. Gleason score was upgraded in 62 of 137 (45%) patients at TPM biopsy. The negative predictive values of mp-MRI score 1 to 2 for predicting that cancer remained low risk (according to each definition) were 75%, 100%, 83%, and 100% for definitions 1, 2, 3, and 4, respectively. An mp-MRI score of 4 to 5 had positive predictive values for upgrade or upsize of 59%, 67%, 75%, and 69% for definitions 1, 2, 3, and 4, respectively.
  
  
  CONCLUSIONS
  The presence of an mp-MRI lesion in men with low-risk prostate cancer on TRUS biopsy confers, in most patients, a high likelihood that higher-risk disease will be present (either Gleason pattern 4 or a significant cancer burden). Conversely, if a lesion is not seen on mp-MRI, the attribution of low-risk grade or cancer burden is much more likely to be correct. Mp-MRI might therefore be used to triage men for resampling biopsies before entering active surveillance.
authors: Department of Urology, University College London Hospital NHS Foundation Trust, London, UK; Department of Urology, Faculty of medicine, Fayoum University, Fayoum, Egypt. Electronic address: mohamed.azeez.10@ucl.ac.uk.
authors: Mohamed
authors: M
authors: Abd-Alazeez
authors: Division of Surgery and Interventional Science, University College London, London, UK.
authors: Hashim U
authors: HU
authors: Ahmed
authors: Department of Urology, University College London Hospital NHS Foundation Trust, London, UK; Barts Cancer Institute, Queen Mary University of London, London, UK.
authors: Manit
authors: M
authors: Arya
authors: Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK.
authors: Clare
authors: C
authors: Allen
authors: Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK; Centre for Medical Imaging, University College London, London, UK.
authors: Nikolaos
authors: N
authors: Dikaios
authors: Department of Histopathology, University College London Hospitals NHS Foundation Trust, London, UK.
authors: Alex
authors: A
authors: Freeman
authors: Department of Urology, University College London Hospital NHS Foundation Trust, London, UK; Division of Surgery and Interventional Science, University College London, London, UK.
authors: Mark
authors: M
authors: Emberton
authors: Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK.
authors: Alex
authors: A
authors: Kirkham
mesh_terms: D000368:Aged; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D017430:Prostate-Specific Antigen
keywords: Active surveillance; Multiparametric MRI; Prostate cancer; Template biopsy