Lung Cancer Screening with Low-Dose CT: a Meta-Analysis

Abstract

BACKGROUND: Randomized controlled trials have evaluated the efficacy of low-dose CT (LDCT) lung cancer screening on lung cancer (LC) outcomes. OBJECTIVE: Meta-analyze LDCT lung cancer screening trials. METHODS:We identified studies by searching PubMed, Google Scholar, the Cochrane Registry, ClinicalTrials.gov, and reference lists from retrieved publications. We abstracted data on study design features, stage I LC diagnoses, LC and overall mortality, false positive results, harm from invasive diagnostic procedures, overdiagnosis, and significant incidental findings. We assessed study quality using the Cochrane risk-of-bias tool. We used randomeffects models to calculate relative risks and assessed effect modulators with subgroup analyses and metaregression. RESULTS: We identified 9 studies that enrolled 96,559 subjects. The risk of bias across studies was judged to be low. Overall, LDCT screening significantly increased the detection of stage I LC, RR = 2.93 (95% CI, 2.16-3.98), I 2 = 19%, and reduced LC mortality, RR = 0.84 (95% CI, 0.75-0.93), I 2 = 0%. The number needed to screen to prevent an LC death was 265. Women had a lower risk of LC death (RR = 0.69, 95% CI, 0.40-1.21) than men (RR = 0.86, 95% CI, 0.66-1.13), p value for interaction = 0.11. LDCT screening did not reduce overall mortality, RR = 0.96 (95% CI, 0.91-1.01), I 2 = 0%. The pooled false positive rate was 8% (95% CI, 4-18); subjects with false positive results had < 1 in 1000 risk of major complications following invasive diagnostic procedures. The most valid estimates for overdiagnosis and significant incidental findings were 8.9% and 7.5%, respectively. DISCUSSION: LDCT screening significantly reduced LC mortality, though not overall mortality, with women appearing to benefit more than men. The estimated risks for false positive results, screening complications, overdiagnosis, and incidental findings were low. Long-term survival data were available only for North American and European studies limiting generalizability.

Lung Cancer Screening with Low-Dose CT in Smokers: A Systematic Review and Meta-Analysis

“…Based on a systematic literature review, we performed a meta-analysis of eight RCTs on LDCT lung cancer screening, including the latest results from European trials published in 2020, comprising a total of more than 87,000 participants. The estimated relative reduction of lung cancer mortality by screening with LDCT was 20% when compared to no screening and 12% across all considered studies, which confirms earlier studies [70][71][72][73]. Although the meta-analysis of included studies did not provide proof of a benefit in all-cause mortality, the effect estimates of most individual studies tend in the same direction as for the lungcancer-specific mortality and indicate a protective effect.…”

A narrative review of lung cancer screening in underserved populations

“…Despite the clear survival benefit of LDCT screening in appropriate patients, there has been a relatively low adherence to these guidelines in clinical practice (8)(9)(10). In addition, several studies have described disparities in the use of LDCT screening in underserved populations, including racial/ethnic minorities (11,12), those living in rural areas with more limited access to care (13), and other vulnerable populations (14,15).…”

A narrative review of lung cancer screening implementation: increasing utilization of evidence-based practice

“…The false positive rate is calculated by dividing the number of false positives by the number of individuals screened with LDCT. Reported false positive rates vary among studies in the literature, ranging from 0.6% to 96% among systematic reviews and meta-analyses (7)(8)(9)(10)13,14). This variability is largely due to differences in the definition of a positive exam.…”

“…The rate of estimated ranges from 0-67% in the literature (9,(13)(14)(15). Usman Ali et al (9) reported an overdiagnosis rate of 10.99-25.83% depending on the thresholds used to determine overdiagnosis across studies (44,75,77,78): lead time 5.5 years with mean sojourn time 2 years, lead time ≥5 years, tumor size 30 mm, and tumor volume doubling time ≥400 days.…”