Biennial low-dose CT (LDCT) lung cancer screening that includes never smokers may be cost-effective and warrants consideration in Singapore, according to a modeling study published July 8 in JAMA Network Open.
In an economic evaluation using a Markov cohort model, researchers from Singapore’s National Healthcare Group found that limiting screening to smokers remained the most cost-effective option, but that that approach left 37% of lung cancers undetected.
“This economic evaluation simulated 4 LDCT screening strategies in Singapore using a 9-state Markov cohort and found a fundamental efficiency-coverage trade-off,” noted lead author Ruijie Li, PhD, and colleagues.
Lung cancer is the leading cause of cancer death in Singapore, with approximately 48% of cases occurring in individuals who have never smoked and 82% diagnosed at late stages (stage III or IV). Current screening guidelines modeled on U.S. and European criteria exclude never smokers entirely, the authors noted, and thus they explored whether LDCT screening could be cost-effective in these individuals.
The researchers built a 9-state Markov cohort model simulating Singapore adults aged 30 to 100 years old, parameterized with national life tables, cancer registry data, and smoking prevalence figures. Four scenarios were compared: no screening; the 2021 U.S. Preventive Services Task Force (USPSTF) criteria, which limits annual screening to eligible smokers aged 50 to 80 years old; a universal annual program modeled on a never-smoker screening trial from Taiwan; and a hypothetical “Singapore expanded” strategy offering biennial screening to all adults ages 50 to 75.
According to the analysis, smoker-only screening under the USPSTF’s criteria produced the lowest incremental cost-effectiveness ratio (ICER) of the four strategies, approximately 8,741 Singapore dollars (S$) per quality-adjusted life-year (QALY) for men (U.S. $6,523/QALY) and S$6,480 for women (U.S. $4,836/QALY). However, this approach reached only about 8% of men and 2% of women in the general population due to its narrow eligibility, the researchers reported.
Extending coverage to the proposed universal Singapore expanded strategy raised the ICER to about S$86,312 per QALY for men (U.S. $64,412/QALY) and S$80,881 for women, which was still below the study’s S$100,000 cost-effectiveness benchmark. Lastly, across one million simulations, the Singapore expanded strategy came out as the most cost-effective option in 61.1% of runs for men and 72.1% of runs for women, at a willingness-to-pay threshold of S$100,000 per QALY, according to the findings.
“These findings suggest that biennial screening including never smokers falls below conventional cost-effectiveness thresholds and warrants consideration in Singapore,” the authors wrote.
Ultimately, the researchers recommended adopting USPSTF-aligned LDCT screening as a practical immediate step, and called for validated risk-prediction models specific to Asian never-smoking populations before universal screening is adopted.
The full study is available here.