title: Systematic review and meta-analysis of the accuracy of MRI and endorectal ultrasound in the restaging and response assessment of rectal cancer following neoadjuvant therapy.
abstract: OBJECTIVE
  Restaging imaging by MRI or endorectal ultrasound (ERUS) following neoadjuvant chemoradiotherapy is not routinely performed, but the assessment of response is becoming increasingly important to facilitate individualization of management.
  
  
  METHODS
  A search of the MEDLINE and Scopus databases was performed for studies that evaluated the accuracy of restaging of rectal cancer following neoadjuvant chemoradiotherapy with MRI or ERUS against the histopathological outcome. A systematic review of selected studies was performed. The methodological quality of studies that qualified for meta-analysis was critically assessed to identify studies suitable for inclusion in the meta-analysis.
  
  
  RESULTS
  Sixty-three articles were included in the systematic review. Twelve restaging MRI studies and 18 restaging ERUS studies were eligible for meta-analysis of T-stage restaging accuracy. Overall, ERUS T-stage restaging accuracy (mean [95% CI]: 65% [56-72%]) was nonsignificantly higher than MRI T-stage accuracy (52% [44-59%]). Restaging MRI is accurate at excluding circumferential resection margin involvement. Restaging MRI and ERUS were equivalent for prediction of nodal status: the accuracy of both investigations was 72% with over-staging and under-staging occurring in 10-15%.
  
  
  CONCLUSIONS
  The heterogeneity amongst restaging studies is high, limiting conclusive findings regarding their accuracies. The accuracy of restaging imaging is different for different pathological T stages and highest for T3 tumours. Morphological assessment of T- or N-stage by MRI or ERUS is currently not accurate or consistent enough for clinical application. Restaging MRI appears to have a role in excluding circumferential resection margin involvement.
authors.affiliation: Division of Cancer Surgery, Colorectal Surgery Department, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.|Department of Surgery, St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Memon
authors.affiliation: Division of Cancer Surgery, Colorectal Surgery Department, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.|Department of Surgery, St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: A C
authors.initials: AC
authors.lastname: Lynch
authors.affiliation: Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Bressel
authors.affiliation: Department of Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: A G
authors.initials: AG
authors.lastname: Wise
authors.affiliation: Division of Cancer Surgery, Colorectal Surgery Department, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.|Department of Surgery, St Vincent's Hospital, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: A G
authors.initials: AG
authors.lastname: Heriot
mesh_terms: D059186:Chemoradiotherapy, Adjuvant; D019160:Endosonography; D006801:Humans; D008279:Magnetic Resonance Imaging; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*
keywords: MRI; endoscopic ultrasonography; meta-analysis; rectal cancer; staging