title: Should this patient be screened for cancer?
abstract: BACKGROUND
  Advances in imaging technology have provided numerous opportunities for cancer screening but have also raised numerous questions.
  
  
  OBJECTIVE
  Who should be screened and how exactly should screening be performed?
  
  
  OBJECTIVE
  If spiral computed tomography (spiral CT) were being considered for lung cancer screening, for example, important questions would need to be answered: Should nonsmokers be screened? How often should screening take place? What should the diagnostic work-up be after abnormal findings were seen on spiral CT?
  Randomized, controlled trials (RCTs) are the most valid method for determining which medical interventions are most effective. These trials are particularly useful in the evaluation of screening because they eliminate the early detection biases that may result in groosly misleading survival statistics.
  
  
  CONCLUSIONS
  Randomized, controlled trials of screening are subject to other biases, and their results may be difficult to generalize. In addition, because they require an enormous number of participants and many years of follow-up, RCTs can be applied only to a small proportion of the questions about cancer screening.
  Quantitative decision analysis can be applied to the remaining questions and help inform decision making about cancer screening.
authors.affiliation: Department of Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA. william.black@hitchcock.org
authors.forename: W C
authors.initials: WC
authors.lastname: Black
mesh_terms: D015982:Bias; D003661:Decision Support Techniques; D018572:Disease-Free Survival; D006801:Humans; D008017:Life Expectancy; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000517:prevention & control*; D008390:Markov Chains; D008403:Mass Screening / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians'; D016032:Randomized Controlled Trials as Topic; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data; D014481:United States