title: Efficacy of 3-Dimensional Endorectal Ultrasound for Staging Early Extraperitoneal Rectal Neoplasms.
abstract: BACKGROUND
  Adequate oncologic staging of rectal neoplasia is important for treatment and prognostic evaluation of the disease. Diagnostic methods such as endorectal ultrasound can assess rectal wall invasion and lymph node involvement.
  
  
  OBJECTIVE
  The purpose of this study was to correlate findings of 3-dimensional endorectal ultrasound and pathologic diagnosis of extraperitoneal rectal tumors with regard to depth of rectal wall invasion, lymph node involvement, percentage of rectal circumference involvement, and tumor extension.
  
  
  METHODS
  Consecutive patients with extraperitoneal rectal tumors were prospectively assessed by 3-dimensional endorectal ultrasound blind to other staging methods and pathologic diagnosis.
  
  
  METHODS
  Patients who underwent endorectal ultrasound followed by surgery were included in the study.
  
  
  METHODS
  The study was conducted at a single academic institution.
  
  
  METHODS
  Sensitivity, specificity, positive and negative predictive values, area under curve, and κ coefficient between 3-dimensional endorectal ultrasound and pathologic diagnosis were determined. Intraclass correlation coefficient was calculated for tumor extension and percentage of rectal wall involvement.
  
  
  RESULTS
  Forty-four patients (27 women; mean age = 63.5 years) were evaluated between September 2010 and June 2014. Most lesions were malignant (72.7%). For depth of submucosal invasion, 3-dimensional endorectal ultrasound showed sensitivity of 77.3%, specificity of 86.4%, positive predictive value of 85.0%, a negative predictive value of 79.2%, and an area under curve of 0.82. The weighted κ coefficient for depth of rectal wall invasion staging was 0.67, and there was no agreement between 3-dimensional endorectal ultrasound and pathologic diagnosis for lymph node involvement (κ = -0.164). Intraclass correlation coefficient for lesion extension and percentage of rectal circumference involvement were 0.45 and 0.66. A better correlation between 3-dimensional endorectal ultrasound and pathologic diagnosis was observed in tumors <5 cm and with <50% of rectal wall involvement.
  
  
  CONCLUSIONS
  The relatively small sample size of patients with early rectal lesions referred directly for surgery could represent a potential selection bias.
  
  
  CONCLUSIONS
  Three-dimensional endorectal ultrasound was effective for determining rectal wall invasion and lesion extension in tumors <5 cm and with <50% of rectal wall invasion but was limited for detecting lymph node involvement in early rectal lesions.
authors.affiliation: Department of Gastroenterology, Colorectal Surgery Service, Hospital das Clínicas of University of São Paulo, School of Medicine, São Paulo, Brazil.
authors.forename: Rodrigo Ambar
authors.initials: RA
authors.lastname: Pinto
authors.forename: Isaac José Felippe
authors.initials: IJ
authors.lastname: Corrêa Neto
authors.forename: Sérgio Carlos
authors.initials: SC
authors.lastname: Nahas
authors.forename: Caio Sérgio
authors.initials: CS
authors.lastname: Rizkalah Nahas
authors.forename: Carlos Frederico
authors.initials: CF
authors.lastname: Sparapan Marques
authors.forename: Ulysses
authors.initials: U
authors.lastname: Ribeiro Junior
authors.forename: Fábio Shiguehissa
authors.initials: FS
authors.lastname: Kawaguti
authors.forename: Ivan
authors.initials: I
authors.lastname: Cecconello
mesh_terms: D019540:Area Under Curve; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010537:Peritoneum / Q000000981:diagnostic imaging / Q000473:pathology; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome