How many individuals must be screened to reduce oral cancer mortality rate in the Western context? A challenge

OBJECTIVE: Controlling oral cancer (OC) through screening is appealing. Advantages of this are as follows: OC is often preceded by visible premalignant lesions, earlystage 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.