title: The accuracy of MRI, endorectal ultrasonography, and computed tomography in predicting the response of locally advanced rectal cancer after preoperative therapy: A metaanalysis.
abstract: BACKGROUND
  To perform a metaanalysis to determine and compare the diagnostic performance of MRI, endorectal ultrasonography (ERUS), and computed tomography (CT) in predicting the response of locally advanced rectal cancer after preoperative therapy.
  
  
  METHODS
  All previously published articles on the role of MRI, CT, and/or ERUS in predicting the response of rectal cancer to preoperative therapy were collected. We divided the objective in 3 parts: the accuracy to assess (i) complete response, (ii) to detect T4 tumors with invasion to the circumferential resection margin (CRM), and (iii) to predict the presence of lymph node metastasis. The pooled estimates of, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated using a bivariate mixed effect analysis.
  
  
  RESULTS
  Forty-six studies comprising 2,224 patients were included. (i) The pooled accuracy to assess complete tumor response were (a) 75% for MRI, (b) 82% for ERUS, (c) and 83% for CT. (ii) Pooled accuracy to detect T4 tumors with invasion to the CRM were (a) 88% and (b) 94% for ERUS. (iii) Pooled accuracy to predict the presence of lymph node metastasis was (a) 72% for MRI, (b) 72% for ERUS, (c) and 65% for CT.
  
  
  CONCLUSIONS
  MRI, CT, and ERUS cannot be used to predict complete response of locally advanced rectal cancer after CRT. In addition, the positive predictive value for these imaging techniques is low for the assessment of tumor invasion in the CRM. The accuracy of the modalities to predict the presence of metastatic lymph node disease is also low.
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Ellen A
authors.initials: EA
authors.lastname: de Jong
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Josianne C E M
authors.initials: JC
authors.lastname: ten Berge
authors.affiliation: Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Roy S
authors.initials: RS
authors.lastname: Dwarkasing
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Anton P
authors.initials: AP
authors.lastname: Rijkers
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address: c.vaneijck@erasmusmc.nl.
authors.forename: Casper H J
authors.initials: CH
authors.lastname: van Eijck
mesh_terms: D059248:Chemoradiotherapy / Q000379:methods; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020360:Neoadjuvant Therapy / Q000379:methods*; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome