title: The incidence of colon cancer among patients diagnosed with left colonic or sigmoid acute diverticulitis is higher than in the general population.
abstract: BACKGROUND
  Considering the low incidence of colon cancer after an initial episode of colonic diverticulitis in some categories of patients, some authors suggested to exempt them from colonoscopy. However, this incidence has never been compared to that of a reference population, and predictors of cancer are still poorly investigated. We aimed to determine the 1-year incidence of colon cancer at the site of diverticulitis in patients diagnosed with left colonic or sigmoid acute diverticulitis, to compare this incidence to a reference population to state whether endoscopy is required or not, and to identify predicting factors of cancer to better target subpopulations needing that examination.
  
  
  METHODS
  All patients admitted at the University Hospitals of Geneva for left colonic or sigmoid acute diverticulitis were included. Patients with a previous history of colon cancer or non-available for follow-up were excluded. Demographic data, haemoglobin values, and the Hinchey score were documented. This cohort was matched with the Geneva Cancer Registry to look for cancer occurrence at the site of diverticulitis within 1 year. Predictors of cancer were assessed using univariate logistic regression and the risk of cancer by comparing observed cases to a reference population using standardized incidence ratios.
  
  
  RESULTS
  The final cohort included 506 patients. Eleven (2.2 %) had a diagnosis of cancer at the site of diverticulitis within 1 year. The mean age was significantly different between patients with cancer and others. No predictor of cancer could be identified, except a trend for an increased risk with advancing age (p = 0.067). The standardized incidence ratios showed a 44-fold increased risk of cancer among the cohort compared to the reference population.
  
  
  CONCLUSIONS
  Colonoscopy should be continued after an initial diagnosis of left colonic or sigmoid acute diverticulitis, irrespective of the clinical or radiological presentations.
authors: Clinic for Visceral and Transplantation Surgery, Department of Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. jeremy.meyer@hcuge.ch.
authors: Jeremy
authors: J
authors: Meyer
authors: Clinic for Visceral and Transplantation Surgery, Department of Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. theothomopoulos@yahoo.com.
authors: Theodoros
authors: T
authors: Thomopoulos
authors: Geneva Cancer Registry, Global Health Institute, University of Geneva, Boulevard de la Cluse 55, 1205, Geneva, Switzerland. massimo.usel@unige.ch.
authors: Massimo
authors: M
authors: Usel
authors: Clinic for Visceral and Transplantation Surgery, Department of Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. ergys.gjika@hcuge.ch.
authors: Ergys
authors: E
authors: Gjika
authors: Geneva Cancer Registry, Global Health Institute, University of Geneva, Boulevard de la Cluse 55, 1205, Geneva, Switzerland. christine.bouchardymagnin@unige.ch.
authors: Christine
authors: C
authors: Bouchardy
authors: Clinic for Visceral and Transplantation Surgery, Department of Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. philippe.morel@hcuge.ch.
authors: Philippe
authors: P
authors: Morel
authors: Clinic for Visceral and Transplantation Surgery, Department of Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211, Geneva 14, Switzerland. frederic.ris@hcuge.ch.
authors: Frédéric
authors: F
authors: Ris
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D003113:Colonoscopy; D004239:Diverticulitis, Colonic / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012810:Sigmoid Diseases / Q000150:complications*
keywords: Colon cancer; Colon carcinoma; Colonoscopy; Endoscopy; Reference population; Risk
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