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

Abstract

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. 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. 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 < 0.001; I2 = 0%) and DFS (53.3% vs. 44.8%; fixed effects models: RR=0.85; 95% CI=[0.76, 0.95]; p=0.003; I2 = 41.7%) rates than patients without 4L LNDS. Moreover, dissection of 4L lymph node was significantly associated with better OS (fixed effects model: HR=0.66; 95% CI=[0.57, 0.76]; p < 0.001; I2 = 45.7%) and DFS (fixed effects model: HR=0.67; 95% CI=[0.52, 0.87]; p=0.003; I2 = 0%). No significant heterogeneities were observed. Dissection of 4L lymph node could significantly improve both 5-year OS and DFS rates and 4L LND was a favorable prognostic factor for patients with left-sided NSCLC.