Outcomes of the first national oral cancer screening programme in Taiwan, 2004-2022: a population-based study.

Objective: This study evaluates whether Taiwan's national oral cancer screening programme, implemented in 1999, has led to a reduction in late-stage oral cancer and mortality.

Design: An observational population-based ecological cohort study (2004-2022) using data from the Taiwan Cancer Registry, a nationwide cancer registry.

Setting: Taiwan, an island nation with a population of 23.5 million.

Participants: The entire male population in the nation diagnosed with oral cancer between 2004 and 2022.

Main outcome measures: Change in stage-specific, age-standardised incidence and mortality of oral cancer and their annual percentage change (APC). We hypothesised that an effective screening programme would lead to an increase in early-stage cancer diagnoses while reducing late-stage cancer incidence and mortality.

Results: A total of 92 342 males were diagnosed with oral cancer in Taiwan between 2004 and 2022. Following the introduction of the national oral cancer screening programme, the incidence of early-stage (stages 0-1) oral cancer increased 2.4-fold from 6.6 to 14.5 per 100 000 males between 2004 and 2013 (APC: 11.3% (95% CI 9.4% to 13.5%), p<0.001). However, early-stage incidence subsequently declined to 11.8 per 100 000 males by 2022 (APC: -3.2% (95% CI -5.2% to -1.6%), p<0.001), corresponding to a period of decreased screening uptake between 2015 and 2022. The late-stage (stages 2-4) oral cancer increased from 24.5 to 28.3 per 100 000 males between 2004 and 2009 (APC: 3.3% (95% CI 1.8% to 6.6%), p<0.001) and then remained relatively stable between 2009 and 2022 (APC: 0.1% (95% CI -0.5% to 0.5%), p=0.65). Oral cancer mortality increased from 14.4 to 16.6 per 100 000 males over the entire examined period between 2004 and 2022 (APC: 0.76% (95% CI 0.5% to 1.1%), p<0.001), showing no observed decline despite two decades of screening efforts and a continued decrease in prevalence of betel quid use.

Conclusions: Although oral cancer screening detected more early-stage cancer, no reduction in population late-stage incidence or mortality was observed. Therefore, reducing betel quid and cigarette consumption should be the primary focus for oral cancer control. The public health response to oral cancer should borrow from lessons learnt in tobacco control.