title: Quantification of population benefit in evaluation of biomarkers: practical implications for disease detection and prevention.
abstract: BACKGROUND
  With the rapid development of "-omic" technologies, an increasing number of purported biomarkers have been identified for cancer and other diseases. The process of identifying those that are most promising and validating them for use at the population level for prevention and early detection is a critical next step in achieving significant health benefits.
  
  
  METHODS
  In this paper, we propose that in order to effectively translate biomarkers for practical clinical use, it is important to distinguish and quantify the differences between the use of biomarkers and other risk factors to identify preventive interventions versus their use in disease risk prediction and early detection. We developed mathematical models for quantitatively evaluating risk and benefit in use of biomarkers for disease prevention or early detection. Simple numerical examples were used to demonstrate the potential applications of the models for various types of data.
  
  
  RESULTS
  We propose an index which takes into account potential adverse consequences of biomarker-driven interventions - the 'naïve' ratio of population benefit (RPB) - to facilitate evaluating the potential impact of biomarkers on cancer prevention and personalized medicine. The index RPB is developed for both binary and continuous biomarkers/risk factors. Examples with computational analyses are presented in the paper to contrast the differences in using biomarkers/risk factors for prevention and early detection.
  
  
  CONCLUSIONS
  Integrating epidemiologic knowledge into clinical decision making is a key step to translate new biomarkers/risk factors into practical use to achieve health benefits. The RPB proposed in this paper considers the absolute risk of a disease in intervention, and takes into account the risk-benefit effects simultaneously for a marker/exposure at the population level. The RPB illustrates a unique approach to quantitatively assess the risk and potential benefits of using a biomarker/risk factor for intervention in both early detection and prevention.
authors.affiliation: Divisions of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, N,, Seattle, WA 98109, USA. xili@fhcrc.org.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Blount
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Reid
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Vaughan
mesh_terms: D015415:Biomarkers / Q000032:analysis; D042241:Early Diagnosis; D015981:Epidemiologic Factors; D006801:Humans; D008962:Models, Theoretical; D011322:Primary Prevention; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers