Role of low dose computed tomography on lung cancer detection and mortality - an updated systematic review and meta-analysis

Chest low dose computed tomography (LDCT) is reported to be a sensitive tool for the detection of lung cancer at asymptomatic stage, thus reducing mortality. The review assesses the effect of LDCT screening on all-cause mortality, lung cancer mortality and incidence rates. We conducted literature searches of PubMed, SCOPUS, and the Cochrane Library from inception through January 2020 to identify relevant studies assessing the diagnostic accuracy of LDCT for lung cancer. We used Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for reporting this meta-analysis and review. The inclusion criteria were a) Randomized control trials, b) Comparing LDCT to any other form of screening or standard of care, and (c) Primary outcome studied: all-cause mortality, lung cancer-specific mortality, rate of early detection of lung cancer. A total of 11 studies encompassing 97,248 patients were included. When compared with controls (no screening or CXR), LDCT screening was associated with statistically significant reduction in lung cancer mortality (pooled RR 0.86; 95% CI 0.75-0.98); low heterogeneity was observed (I²= 27.86). However, LDCT screening was not associated with statistically significant reduction in all-cause mortality (RR =0.96; 95% CI: 0.92 -1.01). Notably, the LDCT screening was associated with statistically significant increase in lung cancer detection (RR =1.76; 95% CI: 1.14-2.72). LDCT screening has the potential to reduce mortality due to lung cancer among high-risk individuals. LDCT could be considered as a screening modality after careful assessment of other factors like prevalence of TB, proportion of high-risk population, cost, access and availability of LDCT.