The impact of the highest mediastinal lymph node metastasis on postoperative recurrence and survival in non-small cell lung cancer patients

Abstract

Objective: To examine whether the highest mediastinal lymph node (HMLN) metastasis had an influence on postoperative recurrence and survival among non-small cell lung cancer (NSCLC) patients with pN2 lymph node metastasis. Methods: A total of 261 patients who underwent radical resection of lung cancer and systematic lymph node dissection in the Department of Thoracic Surgery of Peking University First Hospital from January 2007 to December 2016 were retrospectively analyzed. There were 180 males and 81 females, aged (61.5±9.4) years (range: 31 to 83 years). There were 128 cases of HMLN-positive and 133 cases of HMLN-negative. They were pathologically confirmed N2 stage NSCLC and postoperative recurrence and survival were followed up. The Kaplan-Meier method was used to calculate disease-free survival (DFS) and overall survival (OS) curves according to whether HMLN metastasize or not. The Cox proportional hazards regression model was used for the prognostic analysis. Results: The median DFS and the median OS of the whole group were 28 months and 44 months, respectively. The median DFS in HMLN-positive and HMLN-negative patients was 19 months and 33 months, respectively (P=0.005). The median OS of HMLN-positive and HMLN-negative group was 37 months and 49 months, respectively (P=0.005). Multivariate analysis showed that pneumonectomy and visceral pleural invasion were independent risk factors for both postoperative OS (HR=1.85, 95%CI: 1.25 to 2.72, P=0.002; HR=1.82, 95%CI: 1.30 to 2.56, P=0.007) and DFS (HR=1.61, 95%CI: 1.10 to 2.35, P=0.014; HR=1.77, 95%CI: 1.27 to 2.46,P=0.001). HMLN metastasis and lymphovascular invasion were independent risk factors for only postoperative DFS (HR=1.39, 95%CI: 1.03 to 1.87, P=0.030; HR=1.40, 95%CI: 0.99 to 1.81, P=0.042). Conclusions: For patients of pN2 stage NSCLC, both postoperative recurrence and long-term survival were significantly worse in the HMLN metastatic group. In addition, pneumonectomy and visceral pleural invasion were unfavorable factors that affected both recurrence and overall survival. HMLN metastasis and lymphovascular invasion could shorten the postoperative time for DFS.