title: Combined endorectal ultrasonography and strain elastography for the staging of early rectal cancer.
abstract: OBJECTIVE
  Strain elastography is a novel approach to rectal tumour evaluation. The primary aim of this study was to correlate elastography to pT stages of rectal tumours and to assess the ability of the method to differentiate rectal adenomas (pT0) from early rectal cancer (pT1-2). Secondary aims were to compare elastography with endorectal ultrasonography (ERUS) and to propose a combined strain elastography and ERUS staging algorithm.
  
  
  METHODS
  In all, 120 consecutive patients with a suspected rectal tumour were examined in this staging study. Patients receiving surgery without neoadjuvant radiotherapy were included (n = 59). All patients were examined with ERUS and elastography. Treatment decisions were made by multidisciplinary team (MDT) assessment, without considering the strain elastography examination.
  
  
  RESULTS
  Histopathology identified 21 adenomas, 13 pT1, 9 pT2, 15 pT3 and one pT4. Mean elastography strain ratios were predictive of T stage (P = 0.01). Differentiation of adenomas from early rectal cancer (pT1-2) had sensitivity, specificity and accuracy of 0.82, 0.86 and 0.84 for elastography and 0.82, 0.62 and 0.72 for ERUS. A combined staging algorithm was developed to identify tumours eligible for local resection. Based on MDT evaluation 32% of tumours later identified as pT0 or pT1 were treated with total mesorectal excision, even though a local excision might have sufficed. Combined ERUS and elastography evaluation would have significantly reduced this number to 9% (P = 0.008).
  
  
  CONCLUSIONS
  Elastography may improve the staging of adenomas and early rectal cancer compared with ERUS alone. Combined ERUS and elastography assessment is likely to further improve the selection of patients for local resection.
authors.affiliation: Department of Surgery, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: J E R
authors.initials: JE
authors.lastname: Waage
authors.forename: S P
authors.initials: SP
authors.lastname: Bach
authors.forename: F
authors.initials: F
authors.lastname: Pfeffer
authors.forename: S
authors.initials: S
authors.lastname: Leh
authors.forename: R F
authors.initials: RF
authors.lastname: Havre
authors.forename: S
authors.initials: S
authors.lastname: Ødegaard
authors.forename: G
authors.initials: G
authors.lastname: Baatrup
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000368:Aged; D055088:Early Detection of Cancer / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D019160:Endosonography / Q000379:methods*; D006801:Humans; D009367:Neoplasm Staging / Q000379:methods; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D012680:Sensitivity and Specificity
keywords: Rectal cancer; early-stage rectal neoplasms; elastography; endorectal ultrasound; strain ratio