The nationwide oral cancer screening program was launched for high-risk people (tobacco smokers or betel-nut chewers) in 1999 in Taiwan, but no study has taken the prevalence of tobacco smoking and betel-nut chewing into account for evaluating the impact of the screening program on oral cancer mortality. This study incorporated the risk fraction method with interrupted time-series analysis to evaluate the impact of the nationwide oral mucosal screening program among men in Taiwan. This study estimated the expected oral cancer mortality trend if the screening program had not launched in 1999, which revealed that the increasing oral cancer mortality trend would level off after 2009 due to the declining prevalence of tobacco smoking and betel-nut chewing. In 2000-2007, the percentage changes between the observed (implementation of the screening program) and expected (if the screening program had not launched) oral cancer mortality rate was not statistically significant for each age group. In 2008-2020, the significant percentage changes were -178% (99% CIs: -140.8 to -215.2), -75.4% (-59.4 to -91.4), -33.7% (-24.7 to -42.7), -18.8% (-12.0 to -25.6), and -15.3% (-9.5 to -21.2) for age groups of 30-34, 35-39, 40-44, 45-49, and 50-54, respectively. In addition to its influence on tobacco smoking and betel-nut chewing, the oral mucosal screening program was associated with the reduction of oral cancer mortality among men in Taiwan.
Keywords: interrupted time-series analysis; oral cancer; oral mucosal screening; risk fraction.