Clinical Significance Of Intrapulmonary Lymph Node Dissection In Pathological Stage Ia Non-Small Cell Lung Cancer: A Propensity Score Matching Analysis

Background This study aimed to investigate the prognostic impact of intrapulmonary lymph node (ILN, stations 13-14) dissection on disease-free survival (DFS) in stage IA non-small cell lung cancer (NSCLC) patients in order to facilitate a more suitable determination of surgical strategies for early-stage cases.Methods We retrospectively analyzed 416 patients with pathological stage IA NSCLC from February 2016 to November 2019. The patients were divided into a group with ILN dissection (ILND+ group) and a group without ILN dissection (ILND- group). DFS was compared using the Kaplan-Meier method and compared statistically using the log-rank test before and after propensity score matching (PSM). Subgroup analysis of DFS stratified based on tumor size was also calculated.Results Both before and after PSM, the four-year DFS of the ILND+ group was greatly increased compared to that of ILND- group (90.1% vs. 79.7%, p = 0.003; 95.5% vs. 80.6%, p = 0.003, respectively) and multivariable cox regression analysis revealed ILN dissection was an independent factor favoring DFS in stage IA NSCLC (p = 0.016 and p = 0.015, respectively). Subgroup analysis revealed the four-year DFS was comparable between the ILN (D+) and ILND- groups with regard to tumor size <= 1.5 cm (90.6% vs. 92.7%, p = 0.715). However, the ILN (D+) group was found to have a better oncological outcome compared with the ILND- group with regard to tumor size >1.5 cm (90.0% vs. 73.8%, p = 0.003).Conclusions The prognostic impact of ILN dissection on patients with stage IA NSCLC appears to be significantly influenced by tumor size, and this should be taken into account when choosing the most appropriate therapeutic modality.