title: Previous transanal endoscopic microsurgery for rectal cancer represents a risk factor for an increased abdominoperineal resection rate.
abstract: BACKGROUND
  Transanal endoscopic microsurgery (TEM) represents a surgical option in the treatment of selected early rectal cancers. However, when definitive histopathology shows negative prognostic factors, rectal resection with total mesorectal excision (TME) is recommended to reduce the risk of recurrence. No studies have yet analyzed the impact of previous TEM on the perioperative outcomes of immediate laparoscopic TME (LTME) for rectal cancer. The aim of this study was to evaluate the perioperative outcomes of LTME after TEM for rectal cancer.
  
  
  METHODS
  This study was a retrospective analysis of a prospective database. All patients undergoing LTME within 8 weeks after full-thickness TEM for rectal cancer between January 2001 and December 2011 were included. Each patient was matched on the basis of demographic and clinical characteristics with two patients undergoing primary LTME for rectal cancer during the same period. Age, gender, body mass index, tumor distance from the anal verge, tumor size, neoadjuvant chemoradiation, previous TEM, rectal wall defect size created during TEM, and intraoperative complications were included in a multivariate analysis to identify risk factors for abdominoperineal resection (APR).
  
  
  RESULTS
  A total of 17 patients undergoing TEM followed by LTME were compared to 34 patients undergoing primary LTME. Mean operative time of LTME after TEM was significantly higher (206 vs. 188 min, P = 0.025). APR was more frequently performed after TEM [odds ratio (OR) 5.25, P = 0.028] and in male patients (OR 9.04, P = 0.034). On multivariate analysis, a previous TEM was the only independent predictor of APR (OR 4.13, P = 0.046). The incidence and severity of postoperative complications were similar in both groups. Mesorectum integrity was complete in all cases.
  
  
  CONCLUSIONS
  LTME after TEM is a challenging procedure, with a significantly higher risk of APR compared to primary LTME. Future improvements in preoperative patient selection for TEM are needed to reduce this risk.
authors.affiliation: Digestive, Colorectal, Oncologic, and Minimally Invasive Surgery, Department of Surgical Sciences, University of Torino, Corso A M Dogliotti 14, 10126 Torino, Italy. mario.morino@unito.it
authors.forename: Mario
authors.initials: M
authors.lastname: Morino
authors.forename: Marco Ettore
authors.initials: ME
authors.lastname: Allaix
authors.forename: Simone
authors.initials: S
authors.lastname: Arolfo
authors.forename: Alberto
authors.initials: A
authors.lastname: Arezzo
mesh_terms: D000005:Abdomen / Q000601:surgery*; D001003:Anal Canal; D005260:Female; D006801:Humans; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D010502:Perineum / Q000601:surgery*; D011183:Postoperative Complications / Q000601:surgery; D011351:Proctoscopy / Q000379:methods*; D012004:Rectal Neoplasms / Q000601:surgery*; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome