Time for Tobacco Elimination: Modelling smoking cessation strategies and lung cancer screening in Singapore

BackgroundLung cancer remains a major public health burden, with poor survival largely driven by late-stage diagnosis. With declining and very low smoking prevalence in Singapore at 4.7% in 2024 among 18-29-year-olds, questions arise about future screening efficiency, eligibility criteria, and the impact of smoking cessation, including tobacco elimination. MethodsWe developed a large-scale microsimulation model calibrated to real-world data, generating individual life histories, smoking trajectories, and disease progression for Singapores 4.18 million residents to project smoking prevalence and lung cancer burden. We evaluated 271 low-dose computed tomography (LDCT) screening strategies (by age, gender, uptake, and frequency) under five tobacco control scenarios, from status quo to a complete smoking ban, between 2025 and 2050. FindingsUnder the status quo, all screening strategies were cost-effective relative to the 2024 GDP per capita threshold ([~]SGD 120,000). Among strategies with [≤]10% overdiagnosis, annual screening of eligible ever-smokers aged 50- 80 years was most life-saving, yielding 51,312 (95% uncertainty interval: 36,821-72,830) QALYs at a total cost of SGD 12.2 (9.7-16.1) billion. Adding an immediate smoking ban increased QALY gains by 2.8 (2.2-3.5) times while reducing the total cost by 23.3% (17.0%-30.0%). Extending eligibility to individuals with lower smoking exposure or a first-degree family history remained cost-effective. InterpretationsTobacco elimination yields substantial health and economic benefits, while well-designed risk-based LDCT screening of residual high-risk populations remains cost-effective, supporting a continued role for screening even in settings with declining smoking prevalence.