title: Accuracy of endorectal ultrasonography and computed tomography for restaging rectal cancer after preoperative chemoradiation.
abstract: BACKGROUND
  Preoperative restaging of irradiated rectal cancer is essential for the planning of optimal therapy. The aim of this study was to compare the accuracy of endorectal ultrasonography (ERUS) and CT in restaging rectal cancer after preoperative chemoradiation and to evaluate the factors affecting the accuracy of ERUS.
  
  
  METHODS
  Eighty-three patients with initial, locally advanced rectal cancer were prospectively evaluated by ERUS (n=60) and CT (n=80) after preoperative chemoradiation and just before surgery. All patients then underwent subsequent surgical resection and complete pathologic staging.
  
  
  RESULTS
  In restaging the depth of invasion, the overall accuracy was 38.3% (23 of 60) by ERUS and 46.3% (37 of 80) by CT. Overstaging was more common than understaging with both imaging modalities. Accuracy for restaging lymph node metastasis was 72.6% (37 of 51) by ERUS and 70.4% (50 of 71) by CT. The predictive value of node-negative cases by ERUS was somewhat lower than that of CT (81.1% versus 85.4%, respectively). Complete pathology-proved remission was not correctly predicted in any of the 11 patients by any imaging modalities. Pathologic T and N staging correlated with the staging accuracy of ERUS (p=0.028 and p=0.001, respectively).
  
  
  CONCLUSIONS
  ERUS and CT may allow good prediction of node-negative rectal cancers, although they are inaccurate modalities for predicting treatment response on the rectal wall. New methods of interpretation and diagnostic criteria for ERUS and CT are essential for increasing the accuracy of cancer prediction in at-risk patients.
authors.affiliation: Department of Surgery, Yongdong Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors.forename: Jung Wook
authors.initials: JW
authors.lastname: Huh
authors.forename: Yoon Ah
authors.initials: YA
authors.lastname: Park
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Jung
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Lee
authors.forename: Seung-Kook
authors.initials: SK
authors.lastname: Sohn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D012007:Rectum; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000379:methods