A new selective mediastinal lymph node dissection for clinical peripheral stage IA invasive non-small-cell lung cancer: a propensity-score matching study

Background: The optimal extent of lymph node resection for early-stage non-small cell lung cancer (NSCLC) remains a topic of debate in the medical community. We aimed to assess the surgical and prognostic outcomes based on the extent of mediastinal lymph node dissection (MLND) for resectable clinical stage IA NSCLC.

Methods: From 2016 to 2018, 1,166 patients with clinical stage IA NSCLC who underwent lobectomy or segmentectomy with complete mediastinal lymph node dissection (C-MLND) or selective mediastinal lymph node dissection (S-MLND) at five hospitals were enrolled. Propensity score matching (PSM) was used to reduce selection bias. Perioperative parameters, postoperative complications, survival and disease control were compared between the groups.

Results: S-MLND and C-MLND were performed on 197 and 969 patients, respectively. After PSM, each group comprised 126 patients and there was no significant difference in 5-year recurrence-free survival (RFS) (C-MLND vs. S-MLND, 87.5% vs. 82.9%; P=0.32) or overall survival (OS) (C-MLND vs. S-MLND, 92.0% vs. 95.9%; P=0.39) between the groups. Similar results were observed for perioperative parameters, pN2 detection (6.3% vs. 4.8%, P=0.11) and recurrence patterns (P=0.28). However, the incidence of postoperative complications was significantly lower in the S-MLND cohort than that in the C-MLND cohort (12.7% vs. 23.0%, P=0.03).

Conclusions: S-MLND demonstrated outcomes that were comparable to those of C-MLND and a reduction in complications, indicating the potential of S-MLND as an alternative approach for selected patients with stage IA NSCLC. Prospective, randomized trials are recommended to confirm these findings and establish clear clinical guidelines.