title: National Cancer Screening Programs and evidence-based healthcare policy in South Korea.
abstract: BACKGROUND
  South Korea has managed its National Cancer Screening Program (NCSP) since 1999 with free cancer screenings for the five major types of cancer (stomach, liver, colorectal, breast, and cervical cancer). Despite the tremendous amount of government funding, the necessity of this policy and scientific evidence pertaining to it have been questioned.
  
  
  OBJECTIVE
  This study reviewed the NCSP's effectiveness and its evidence.
  
  
  RESULTS
  First, the lead-time bias of diagnosis and the length-time bias regarding the average survival time may increase the misunderstanding that the early detection of cancer will contribute to lower mortality rates and higher survival rates. Second, the positive predictive values (PPVs) of the five major types of cancer checked by the NCSP have remained at 0.6-5.7%. The sensitivity of the screening programs also stood at less than 50% on average.
  
  
  CONCLUSIONS
  This study showed that the NCSP program has been less effective, as shown by its low PPVs and sensitivity values, and that its anticipated contribution to lowering the number of cancer-related deaths may have been a product of biased reasoning. To develop the NCSP, adequate explanations of the benefits and potential risks of cancer examinations as well as the accuracy of examinations need to be provided to patients.
authors.affiliation: Center for Community-Based Research, Dana-Farber Cancer Institute, MA, USA; Department of Health Science, Dongduk Women's University, Seoul, South Korea. Electronic address: mins.jung@gmail.com.
authors.forename: Minsoo
authors.initials: M
authors.lastname: Jung
mesh_terms: D055088:Early Detection of Cancer; D019317:Evidence-Based Medicine; D006291:Health Policy; D006801:Humans; D009369:Neoplasms / Q000175:diagnosis / Q000517:prevention & control; D015397:Program Evaluation; D056910:Republic of Korea
keywords: Bias; Cancer screening; Effectiveness; National Program; South Korea