A propensity score matching study of non-grasping mediastinal lymph node dissection versus traditional grasping mediastinal lymph node dissection for non-small cell lung cancer by video-assisted thoracic surgery.

Background: The aim of our study was to compare the efficacy of lymph node (LN) dissection, short-term surgical outcomes, and long-term outcomes between non-grasping en bloc mediastinal lymph node dissection (NE-MLND) and traditional grasping mediastinal lymph node dissection (G-MLND) under video-assisted thoracic surgery (VATS) for non-small cell lung cancer (NSCLC). Methods: We retrospectively analyzed 872 patients with pathological stage I-III NSCLC who underwent VATS. The patient's demographic characteristics, short-term surgical outcomes, overall survival (OS) and disease-free survival (DFS) were assessed. A propensity score-matched (PSM) analysis was performed between NE-MLND and G-MLND to reduce bias, and 349 pairs of patients were matched. Results: Before propensity-score matching, for short-term surgical outcomes, the NE-MLND group had shorter operation time (P<0.001), more LNs removed (N1: P=0.002; N2: P<0.001; N1+ N2: P<0.001), more pleural drainage during the first 3 days after surgery (P<0.001), and longer postoperative hospital stay (P<0.001). For long-term survival outcomes, the NE-MLND group had a longer OS (5-year OS: 71.8% vs. 64.8%, P=0.013), and there was no difference in DFS between the 2 groups (P=0.138). After propensity-score matching, the short-term surgical outcomes were consistent with the results before PSM. The OS and DFS in NE-MLND group were significantly longer than those in the G-MLND group (5-year OS: 76.4% vs. 63.5%, P=0.001 and 5-year DFS: 63.0% vs. 54.6%, P=0.033, respectively). Multivariate analysis showed that NE-MLND was an independent protective factor against OS [G-MLND: hazard ratio (HR) 1.461; 95% confidence interval (CI), 1.130-1.890; P=0.004]. Conclusions: NE-MLND is a safe, acceptable and superior approach to remove mediastinal LNs with shorter operation time. Patients with NSCLC may benefit from NE-MLND, which could lead to better OS and DFS as compared with G-MLND.