title: A comparison of endoscopic localization error rate between operating surgeons and referring endoscopists in colorectal cancer.
abstract: Colonoscopy for colorectal cancer (CRC) has a localization error rate as high as 21 %. Such errors can have substantial clinical consequences, particularly in laparoscopic surgery. The primary objective of this study was to compare accuracy of tumor localization at initial endoscopy performed by either the operating surgeon or non-operating referring endoscopist.
  
  
  
  All patients who underwent surgical resection for CRC at a large tertiary academic hospital between January 2006 and August 2014 were identified. The exposure of interest was the initial endoscopist: (1) surgeon who also performed the definitive operation (operating surgeon group); and (2) referring gastroenterologist or general surgeon (referring endoscopist group). The outcome measure was localization error, defined as a difference in at least one anatomic segment between initial endoscopy and final operative location. Multivariate logistic regression was used to explore the association between localization error rate and the initial endoscopist.
  
  
  
  A total of 557 patients were included in the study; 81 patients in the operating surgeon cohort and 476 patients in the referring endoscopist cohort. Initial diagnostic colonoscopy performed by the operating surgeon compared to referring endoscopist demonstrated statistically significant lower intraoperative localization error rate (1.2 vs. 9.0 %, P = 0.016); shorter mean time from endoscopy to surgery (52.3 vs. 76.4 days, P = 0.015); higher tattoo localization rate (32.1 vs. 21.0 %, P = 0.027); and lower preoperative repeat endoscopy rate (8.6 vs. 40.8 %, P < 0.001). Initial endoscopy performed by the operating surgeon was protective against localization error on both univariate analysis, OR 7.94 (95 % CI 1.08-58.52; P = 0.016), and multivariate analysis, OR 7.97 (95 % CI 1.07-59.38; P = 0.043).
  
  
  
  This study demonstrates that diagnostic colonoscopies performed by an operating surgeon are independently associated with a lower localization error rate. Further research exploring the factors influencing localization accuracy and why operating surgeons have lower error rates relative to non-operating endoscopists is necessary to understand differences in care.
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Arash
authors.initials: A
authors.lastname: Azin
authors.affiliation: Division of General Surgery, William Osler Health System, Etobicoke, ON, Canada.|Division of General Surgery, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Room 8MP-320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Fady
authors.initials: F
authors.lastname: Saleh
authors.affiliation: Division of General Surgery, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Room 8MP-320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Michelle
authors.initials: M
authors.lastname: Cleghorn
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Yuen
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, ON, Canada.|Division of General Surgery, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Room 8MP-320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Timothy
authors.initials: T
authors.lastname: Jackson
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, ON, Canada.|Division of General Surgery, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Room 8MP-320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Allan
authors.initials: A
authors.lastname: Okrainec
authors.affiliation: Division of General Surgery, University of Toronto, Toronto, ON, Canada. Fayez.Quereshy@uhn.ca.|Division of General Surgery, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Room 8MP-320, Toronto, ON, M5T 2S8, Canada. Fayez.Quereshy@uhn.ca.
authors.forename: Fayez A
authors.initials: FA
authors.lastname: Quereshy
mesh_terms: D000368:Aged; D003082:Colectomy; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery*; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D012017:Referral and Consultation; D012189:Retrospective Studies; D066231:Surgeons
keywords: Colonoscopy; Colorectal cancer; Endoscopy; Tumor localization