title: Diagnostic performance of guaiac-based fecal occult blood test in routine screening: state-wide analysis from Bavaria, Germany.
abstract: OBJECTIVE
  Randomized trials have shown that annual or biannual screening by guaiac-based fecal occult blood tests (gFOBTs) reduces colorectal cancer (CRC) mortality. Few clinical studies have evaluated diagnostic performance of gFOBT through validation by colonoscopy in all participants. We aimed for a comprehensive evaluation of diagnostic performance of gFOBT by age and sex under routine screening conditions.
  
  
  METHODS
  Our analysis is based on 20,884 colonoscopies following up a positive gFOBT and 182,956 primary screening colonoscopies documented in a state-wide quality assurance program in Bavaria, Germany, in 2007-2009. Positive likelihood ratios (LR+), which represent an integrative measure of diagnostic performance, were derived, by age groups (55-59, 60-64, 65-69, 70-74 years) and sex, from a joint and comparative analysis of prevalences of colorectal neoplasms in both groups.
  
  
  RESULTS
  Overall LR+ (95% confidence intervals) were 1.11 (1.06-1.15), 1.80 (1.72-1.88), and 5.04 (4.64-5.47) for non-advanced adenoma, advanced adenoma, and cancer, respectively. Assuming a specificity of gFOBT of 95.2%, as recently observed in a German study among 2,235 participants of screening colonoscopy, these LR+ would translate to sensitivities of 5.3%, 8.6%, and 24.2% for the three outcomes, respectively. Diagnostic performance was similarly poor among women and men and across age groups.
  
  
  CONCLUSIONS
  The performance of gFOBT under routine screening conditions is even worse than previously estimated from clinical studies. In routine screening application, gFOBTs are expected to miss more than 9 out of 10 advanced adenomas and 3 out of 4 cancers. These results underline the need and the potential for better noninvasive CRC screening tests.
authors.affiliation: 1] Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany [2] German Cancer Consortium (DKTK), Heidelberg, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Brenner
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoffmeister
authors.affiliation: 1] Gastroenterology Practice, Munich, Germany [2] Bavarian Association of Statutory Health Insurance Physicians, Munich, Germany.
authors.forename: Berndt
authors.initials: B
authors.lastname: Birkner
authors.affiliation: 1] Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany [2] Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Stock
mesh_terms: D000368:Aged; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000517:prevention & control; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D005858:Germany; D006138:Guaiac; D006801:Humans; D007202:Indicators and Reagents; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity
chemical_list: D007202:Indicators and Reagents; D006138:Guaiac