Effects of low-dose computed tomography on lung cancer screening: a systematic review, meta-analysis, and trial sequential analysis

The Nelson mortality results were presented in September 2018. Four other randomized control trials (RCTs) were also reported the latest mortality outcomes in 2018 and 2019. We therefore conducted a meta-analysis to update the evidence and investigate the benefits and harms of low-dose computed tomography (LDCT) in lung cancer screening. Detailed electronic database searches were performed to identify reports of RCTs that comparing LDCT to any other type of lung cancer screening. Pooled risk ratios (RRs) were calculated using random effects models. We identified nine RCTs (n = 97,244 participants). In pooled analyses LDCT reduced lung cancer mortality (RR 0.83, 95% CI 0.76–0.90, I2 = 1%) but had no effect on all-cause mortality (RR 0.95, 95% CI 0.90–1.00). Trial sequential analysis (TSA) confirmed the results of our meta-analysis. Subgroup defined by high quality trials benefitted from LDCT screening in reducing lung cancer mortality (RR 0.82, 95% CI 0.73–0.91, I2 = 7%), whereas no benefit observed in other low quality RCTs. LDCT was associated with detection of a significantly higher number of early stage lung cancers than the control. No significant difference (RR 0.64, 95% CI 0.30–1.33) was found in mortality after invasive procedures between two groups. In meta-analysis based on sufficient evidence demonstrated by TSA suggests that LDCT screening is superiority over usual care in lung cancer survival. The benefit of LDCT is expected to be heavily influenced by the risk of lung cancer in the different target group (smoking status, Asian) being screened.