Race, age at diagnosis and histological characteristics of lung cancer in never-smokers (LCINS) and ever-smokers in low-dose computed tomography (LDCT) screening: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational screening cohort studies
PubMed 38854936 · doi:10.21037/tlcr-23-816
What was done
Systematic review and meta-analysis examining how race, age at diagnosis, and tumor histology differentiate lung cancer detected by low-dose computed tomography (LDCT) screening in never-smokers (NS) versus ever-smokers (ES). Analyses drew on 12 publications with relevant data extracted from 14 studies included in a previous meta-analysis.
What was found
In Asian cohorts (5 Asian and 1 international study), Asian ES had a similar risk of lung cancer diagnosed at baseline LDCT screening compared to Asian NS (RR = 0.96; 95% CI: 0.74–1.24), whereas non-Asian ES had a significantly higher risk than non-Asian NS (RR = 4.56; 95% CI: 2.85–7.28). Baseline lung cancer incidence among NS was approximately 2.3 times higher in Asians than non-Asians (0.62% vs. 0.27%, P = 0.001), while Asian ES had about half the baseline incidence of non-Asian ES (0.65% vs. 1.26%). Based on 4 studies, lung cancer in never-smokers was diagnosed 1.98 years younger than in ever-smokers (95% CI: -3.38 to -0.58) and had a higher proportion of adenocarcinoma (96.58% vs. 70.37%).
Why it matters
These findings suggest that screening criteria optimized for Western, smoking-predominant populations may miss high-risk Asian never-smokers. They provide an epidemiological rationale to explore lower age thresholds and risk models tailored to non-smokers in Asian populations.
Limits
Total individual participant counts were not reported in the abstract. Age at diagnosis comparisons were restricted to only 4 studies. As a meta-analysis of observational screening cohorts, variations in baseline screening protocols, definition of non-smokers, and unmeasured confounders across individual studies could affect pooled risk estimates.
Cited by
- supports Adenocarcinoma is the dominant type of lung cancer in non-smokers.