title: Synchronous colorectal carcinoma: a risk factor in colorectal cancer surgery.
abstract: BACKGROUND
  Synchronous colorectal carcinoma occurs in 1% to 8% of cases. There are little data on the impact of synchronous colorectal cancer on surgical treatment and short-term postoperative outcomes.
  
  
  OBJECTIVE
  The purpose of this work was to evaluate clinical characteristics and treatment patterns of synchronous colorectal carcinoma and their influence on short-term postoperative outcomes in comparison with solitary colorectal carcinoma.
  
  
  METHODS
  This was a population-based observational study. Patient and tumor characteristics, treatment patterns, and postoperative outcomes are described for patients with a solitary and synchronous colorectal carcinoma separately. Multivariable logistic regression analysis was used to analyze the association between synchronous colorectal carcinoma and postoperative complications in comparison with a solitary colorectal carcinoma.
  
  
  METHODS
  The study included in-hospital registration for the Dutch Surgical Colorectal Audit.
  
  
  METHODS
  Patients were those with primary colorectal carcinoma from 2009 to 2011.
  
  
  METHODS
  Severe postoperative complications, reinterventions, and 30-day mortality were measured.
  
  
  RESULTS
  Of 25,413 patients with colorectal cancer, 884 (3.5%) had synchronous colorectal tumors. Patients with synchronous colorectal carcinoma were older and more often of male sex compared with patients with solitary colorectal carcinoma. In ≥ 35% of cases, an extended surgical procedure was conducted (n = 310). In multivariable logistic regression analysis, synchronous colorectal carcinoma was associated with a higher risk of severe postoperative complications (OR, 1.40; 95% CI, 1.20-1.63) and reinterventions (OR, 1.37; 95% CI, 1.14-1.65) compared with solitary colorectal carcinoma but not with higher 30-day mortality (OR, 1.34; 95% CI, 0.96-1.88).
  
  
  CONCLUSIONS
  This study was limited by the data being self-reported. Case-mix adjustment was limited to information available in the data set, and no long-term outcome data were available.
  
  
  CONCLUSIONS
  Synchronous colorectal carcinomas are prevalent in 3.5% of patients and require a different treatment strategy in comparison with solitary colorectal carcinoma. Postoperative outcomes are unfavorable, most likely because of extensive surgery.
authors.affiliation: 1Department of Surgery, Leiden University Medical Centre, Leiden, the Netherlands 2Department of Surgery, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands 3Department of Surgery, Deventer Hospital, Deventer, the Netherlands.
authors.forename: Nicoline J
authors.initials: NJ
authors.lastname: van Leersum
authors.forename: Arend G
authors.initials: AG
authors.lastname: Aalbers
authors.forename: Heleen S
authors.initials: HS
authors.lastname: Snijders
authors.forename: Daniel
authors.initials: D
authors.lastname: Henneman
authors.forename: Michel W
authors.initials: MW
authors.lastname: Wouters
authors.forename: Rob A
authors.initials: RA
authors.lastname: Tollenaar
authors.forename: Eric Hans
authors.initials: EH
authors.lastname: Eddes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy; D015179:Colorectal Neoplasms / Q000401:mortality / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009378:Neoplasms, Multiple Primary / Q000401:mortality / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology* / Q000401:mortality; D012007:Rectum / Q000601:surgery*; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D057566:Self Report; D016896:Treatment Outcome