title: How many individuals must be screened to reduce oral cancer mortality rate in the Western context? A challenge.
abstract: OBJECTIVE
  Controlling oral cancer (OC) through screening is appealing. Advantages of this are as follows: OC is often preceded by visible premalignant lesions, early-stage survival is threefold greater than late-stage survival, and visual screening is inexpensive. Disadvantages of this are as follows: high frequency of false positives, undemonstrated cost-effectiveness, and irregular screening attendance by high-risk individuals. Screening effectiveness in Western countries has not been proven, because of low OC prevalence, which disproportionally increases the number of individuals needed to screen (NNS) to decrease mortality. This study estimated the NNS to obtain an evident decrease in OC mortality rate in the UK.
  
  
  METHODS
  Data gathered from reliable databanks were used. NNS to detect one case (NNScase ) was estimated using a Bayesian approach. NNS to prevent one death (NNSdeath ) was assessed multiplying NNScase by the number of cases that must be screen-detected to prevent one death. NNS to decrease mortality rate by 1% (NNSmortality ) was assessed multiplying NNSdeath by 1% of annual OC deaths.
  
  
  RESULTS
  NNSmortality was overall 1 125 000 (95% confidence interval - 95CI, 690 000-1 870 000), males 551 000 (95CI, 337 000-916 000), and females 571 000 (95CI, 347 000-942 000).
  
  
  CONCLUSIONS
  An OC visual screening campaign capable of producing an evident decrease in mortality rate in the UK requires a large number of adults to be annually and regularly screened.
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Petti
authors.affiliation: WHO Collaborating Centre for oral health-general health, London, UK.|University College London, London, UK.
authors.forename: C
authors.initials: C
authors.lastname: Scully
mesh_terms: D000293:Adolescent; D000328:Adult; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000401:mortality* / Q000517:prevention & control; D011237:Predictive Value of Tests; D015996:Survival Rate; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
keywords: Number Needed to Screen; mortality rate; oral cancer; screening