Survival Benefit of Left Lower Paratracheal (4L) Lymph Node Dissection for Patients with Left-Sided Non-small Cell Lung Cancer: Once Neglected But of Great Importance

Abstract

The aim of this study was to compare survival outcomes between non-small cell lung cancer (NSCLC) patients with or without 4L node dissection (4LND) and to evaluate the potential patient population who will particularly benefit from 4LND. Between January 2009 and December 2015, a total of 2063 patients with primary left-sided NSCLC in the Western China Lung Cancer Database were initially reviewed. After exclusion, 1064 patients were enrolled in this study. A total of 460 patients with 4LND (4LND+ group) were matched with 460 patients without 4LND (4LND- group) using propensity-matched analysis. Disease-free survival (DFS) and overall survival (OS) were analyzed. The metastasis rate of station 4L was 14.6%. Patients with 4LND showed higher DFS (5-year DFS 52.6% vs. 46.7%; hazard ratio [HR] 1.25, 95% confidence interval [CI] 1.03-1.50; p = 0.022) and OS (5-year OS 65.8% vs. 56.3%; HR 1.36, 95% CI 1.10-1.69; p = 0.006) than patients without 4LND. In the multivariate analysis, patients without 4LND (HR 1.33, 95% CI 1.07-1.66; p = 0.011), tumor size > 3cm, lymph node metastasis, and pathologic stage higher than stage I were independent prognostic factors for poor OS. Subgroup analysis according to pathologic TNM stage and N stage showed that stage II, IIIA, and N2 disease indicated better survival outcomes in the 4LND+ group (p = 0.050, p = 0.016, and p = 0.008, respectively). Performing 4LND may bring survival benefits to patients with left-sided NSCLC. We suggest 4LND as a standard procedure for left-sided NSCLC patients with stage II or advanced stage disease.