title: Can multiparametric MRI replace Roach equations in staging prostate cancer before external beam radiation therapy?
abstract: OBJECTIVE
  To investigate the agreement between Roach equations (RE) and multiparametric magnetic resonance imaging (mpMRI) in assessing the T-stage of prostate cancer (PCa).
  
  
  METHODS
  Seventy-three patients with biopsy-proven PCa and previous RE assessment prospectively underwent mpMRI on a 3.0T magnet before external beam radiation therapy (EBRT). Using Cohen's kappa statistic, we assessed the agreement between RE and mpMRI in defining the T-stage (≥T3 vs.T≤2) and risk category according to the National comprehensive cancer network criteria (≤intermediate vs. ≥high). We also calculated sensitivity and specificity for ≥T3 stage in an additional group of thirty-seven patients with post-prostatectomy histological examination (mpMRI validation group).
  
  
  RESULTS
  The agreement between RE and mpMRI in assessing the T stage and risk category was moderate (k=0.53 and 0.56, respectively). mpMRI changed the T stage and risk category in 21.9% (95%C.I. 13.4-33-4) and 20.5% (95%C.I. 12.3-31.9), respectively, prevalently downstaging PCa compared to RE. Sensitivity and specificity for ≥T3 stage in the mpMRI validation group were 81.8% (95%C.I. 65.1-91.9) and 88.5% (72.8-96.1).
  
  
  CONCLUSIONS
  RE and mpMRI show moderate agreement only in assessing the T-stage of PCa, translating into an mpMRI-induced change in risk assessment in about one fifth of patients. As supported by high sensitivity/specificity for ≥T3 stage in the validation group, the discrepancy we found is in favour of mpMRI as a tool to stage PCa before ERBT.
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia - via Colugna, 50-33100, Udine, Italy. Electronic address: rgirometti@sirm.org.
authors.forename: Rossano
authors.initials: R
authors.lastname: Girometti
authors.affiliation: Department of Oncological Radiation Therapy, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia, Piazzale S. M. della Misericordia, 15-33100, Udine, Italy. Electronic address: marco.signor@asuiud.sanita.fvg.it.
authors.forename: Marco Andrea
authors.initials: MA
authors.lastname: Signor
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia - via Colugna, 50-33100, Udine, Italy. Electronic address: martypancot@libero.it.
authors.forename: Martina
authors.initials: M
authors.lastname: Pancot
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia - via Colugna, 50-33100, Udine, Italy. Electronic address: lcereser@sirm.org.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cereser
authors.affiliation: Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia - via Colugna, 50-33100, Udine, Italy. Electronic address: chiara.zuiani@uniud.it.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zuiani
mesh_terms: D000368:Aged; D000465:Algorithms; D001706:Biopsy / Q000379:methods; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010347:Patient Care Planning; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000032:analysis; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D018570:Risk Assessment; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D017430:Prostate-Specific Antigen
keywords: External beam radiation therapy; Magnetic resonance imaging; Prostate cancer; Roach equations; T stage