title: Laparoscopic versus open surgery for T4 colon cancer: evaluation of margin status.
abstract: BACKGROUND
  Laparoscopic resection has been considered a relative contraindication for T4 colonic and rectal lesions due to concern over inadequate margins. The objective of this study was to compare planned laparoscopic and open resections of T4 lesions with respect to the positive margin rate.
  
  
  METHODS
  Data were obtained from the American College of Surgeons National Surgical Quality Improvement Program participant use file to perform a retrospective cohort analysis. The study population consisted of patients that underwent a colorectal resection for a primary T4 lesion during 2011 and 2012. A multiple logistic regression analysis was conducted to determine the adjusted odds ratio (OR) of positive margins based on surgical approach. An inverse probability of treatment weighting (IPTW) analysis was used to account for confounding by indication. A sensitivity analysis including only "as-treated" cases was also performed.
  
  
  RESULTS
  The sub-selected population consisted of 455 and 406 patients in the laparoscopic and open group, respectively. In the original cohort, demographic variables were similar. The open group had a higher incidence of comorbidities, metastatic disease, and emergency cases. Laparoscopic surgery was found to be no different than open surgery with respect to positive margin status (OR 1.10, p = 0.54). After IPTW adjustment, surgical approach remained a nonsignificant predictor of positive margins (OR 1.18, p = 0.31). The "as-treated" analysis also showed that surgical approach had no significant effect on the positive margin rate (OR 1.24, p = 0.24).
  
  
  CONCLUSIONS
  Using this large national surgical database, select patients with T4 lesions who underwent planned laparoscopic colorectal resections did not have a significantly higher positive margin rate compared with patients with open operations. Further research is needed to identify the role of laparoscopy in managing T4b lesions before any consensus can be reached regarding its application in locally advanced colon cancer.
authors.affiliation: Department of Surgery, Toronto Western Hospital - University Health Network, University of Toronto, 399 Bathurst Street, Room 8MP - 320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Elnahas
authors.affiliation: Department of Surgery, Toronto Western Hospital - University Health Network, University of Toronto, 399 Bathurst Street, Room 8MP - 320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Supreet
authors.initials: S
authors.lastname: Sunil
authors.affiliation: Department of Surgery, Toronto Western Hospital - University Health Network, University of Toronto, 399 Bathurst Street, Room 8MP - 320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Jackson
authors.affiliation: Department of Surgery, Toronto Western Hospital - University Health Network, University of Toronto, 399 Bathurst Street, Room 8MP - 320, Toronto, ON, M5T 2S8, Canada.
authors.forename: Allan
authors.initials: A
authors.lastname: Okrainec
authors.affiliation: Department of Surgery, Toronto Western Hospital - University Health Network, University of Toronto, 399 Bathurst Street, Room 8MP - 320, Toronto, ON, M5T 2S8, Canada. Fayez.Quereshy@uhn.ca.|Department of Surgical Oncology, Princess Margaret Cancer Center, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada. Fayez.Quereshy@uhn.ca.
authors.forename: Fayez A
authors.initials: FA
authors.lastname: Quereshy
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D010535:Laparoscopy; D008297:Male; D000072662:Margins of Excision; D012189:Retrospective Studies
keywords: Colorectal cancer; Laparoscopy; Margin status