Dissection of 4L lymph node for left‐sided non‐small cell lung cancer: a meta‐analysis

Background Whether dissection of left lower paratracheal (4L) lymph node has any impact on survival of patients with left‐sided non‐small cell lung cancer (NSCLC) remains unclear. We conducted the first meta‐analysis to compare the survival of patients treated with 4L lymph node dissection (LND) and those without for left‐sided NSCLC. Methods We systematically searched relevant studies from PubMed, Embase, and Web of Science on February 6, 2020. Data for analysis included 5‐year overall survival (OS) and disease‐free survival (DFS) rates, OS, and DFS. We calculated risk ratio (RR) for pooling 5‐year OS and DFS rates and extracted hazard ratio (HR) from multivariate analysis for pooling OS and DFS. Results We finally included three retrospective cohort studies with propensity score‐matched analysis consisting of 2103 patients. Meta‐analysis showed that patients treated with 4L LND yielded significantly higher 5‐year OS (67.7% vs. 54.6%; fixed effects models: RR = 0.75; 95% confidence interval [CI] = [0.67, 0.84]; p