title: Endoscopic ultrasound staging of rectal cancer: diagnostic value before and following chemoradiation.
abstract: BACKGROUND
  Endoscopic ultrasound (EUS) has been shown to be a reliable tool for staging rectal cancer. Nevertheless, the accuracy of EUS after chemoradiation remains unclear; therefore the purpose of the present paper was to compare the accuracy of EUS staging for rectal cancer before and following chemoradiation.
  
  
  METHODS
  Patients with rectal cancer undergoing EUS staging were stratified into two groups. Group I consisted of 66 patients who underwent surgery following EUS staging without preoperative chemoradiation. Group II consisted of 25 patients who had EUS evaluation following chemoradiation. The EUS staging was compared to surgical/pathological staging.
  
  
  RESULTS
  The accuracy of the T staging for group I was 86% (57/66). Inaccurate staging was mainly associated with overstaging EUS T2 tumors. The accuracy of the N staging for group I was 71% (47/66). The accuracy of EUS for a composite T and N staging relevant to treatment decisions in group I was 91%. In group II, the accuracy of T and N staging was 72% (18/25) and 80% (20/25), respectively. Overstaging EUS T3 tumors accounted for most inaccurate staging. The EUS staging predicted post-chemoradiation T0N0 stage correctly in only 50% of cases.
  
  
  CONCLUSIONS
  Preoperative staging of rectal cancer by EUS is a useful modality in determining the need for preoperative chemoradiation. The EUS T staging following chemoradiation appears to be less accurate. Detection of complete response may be insufficient for selecting patients for limited surgical intervention.
authors.affiliation: Department of Gastroenterology, Sheba Medical Center, Tel-Hashomer, Israel. yakov@sheba.health.gov.il
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Maor
authors.forename: Moshe
authors.initials: M
authors.lastname: Nadler
authors.forename: Iris
authors.initials: I
authors.lastname: Barshack
authors.forename: Oded
authors.initials: O
authors.lastname: Zmora
authors.forename: Moshe
authors.initials: M
authors.lastname: Koller
authors.forename: Yulia
authors.initials: Y
authors.lastname: Kundel
authors.forename: Herma
authors.initials: H
authors.lastname: Fidder
authors.forename: Simon
authors.initials: S
authors.lastname: Bar-Meir
authors.forename: Benjamin
authors.initials: B
authors.lastname: Avidan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D019160:Endosonography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D011379:Prognosis; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D015203:Reproducibility of Results; D012189:Retrospective Studies