title: Cost-effectiveness analysis of the optimal threshold of an automated immunochemical test for colorectal cancer screening: performances of immunochemical colorectal cancer screening.
abstract: BACKGROUND
  Most industrialized countries, including France, have undertaken to generalize colorectal cancer screening using guaiac fecal occult blood tests (G-FOBT). However, recent researches demonstrate that immunochemical fecal occult blood tests (I-FOBT) are more effective than G-FOBT. Moreover, new generation I-FOBT benefits from a quantitative reading technique allowing the positivity threshold to be chosen, hence offering the best balance between effectiveness and cost. We aimed at comparing the cost and the clinical performance of one round of screening using I-FOBT at different positivity thresholds to those obtained with G-FOBT to determine the optimal cut-off for I-FOBT.
  
  
  METHODS
  Data were derived from an experiment conducted from June 2004 to December 2005 in Calvados (France) where 20,322 inhabitants aged 50-74 years performed both I-FOBT and G-FOBT. Clinical performance was assessed by the number of advanced tumors screened, including large adenomas and cancers. Costs were assessed by the French Social Security Board and included only direct costs.
  
  
  RESULTS
  Screening using I-FOBT resulted in better health outcomes and lower costs than screening using G-FOBT for thresholds comprised between 75 and 93 ng/ml. I-FOBT at 55 ng/ml also offers a satisfactory alternative to G-FOBT, because it is 1.8-fold more effective than G-FOBT, without increasing the number of unnecessary colonoscopies, and at an extra cost of 2,519 euros per advanced tumor screened.
  
  
  CONCLUSIONS
  The use of an automated I-FOBT at 75 ng/ml would guarantee more efficient screening than currently used G-FOBT. Health authorities in industrialized countries should consider the replacement of G-FOBT by an automated I-FOBT test in the near future.
authors.affiliation: Department of Economics, University of Caen and ERI3 INSERM, Caen, France. celia.berchi@unicaen.fr
authors.forename: Célia
authors.initials: C
authors.lastname: Berchi
authors.forename: Lydia
authors.initials: L
authors.lastname: Guittet
authors.forename: Véronique
authors.initials: V
authors.lastname: Bouvier
authors.forename: Guy
authors.initials: G
authors.lastname: Launoy
mesh_terms: D000368:Aged; D057205:Automation, Laboratory / Q000191:economics; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000191:economics*; D003362:Cost-Benefit Analysis; D006138:Guaiac; D006801:Humans; D007120:Immunochemistry; D007202:Indicators and Reagents; D008403:Mass Screening / Q000191:economics* / Q000379:methods*; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity
chemical_list: D007202:Indicators and Reagents; D006138:Guaiac