Comprehensive analysis of metastatic N1 lymph nodes in completely resected non-small-cell lung cancer

OBJECTIVES The aim of this study was to comprehensively analyse metastatic lymph nodes as prognostic factors after complete resection in N1 non-small-cell lung cancer (NSCLC). METHODS We enrolled 195 patients with pathological N1 NSCLC after complete resection. The number of metastatic lymph nodes and metastatic stations, locations of metastatic lymph nodes, total number of dissected LNs, number of dissected N1 and N2 nodes and the ratio of the number of metastatic N1 nodes to the total number of dissected LNs were evaluated. Univariate analysis by the log-rank test and multivariate analysis by a Cox proportional hazards model were performed to identify prognostic factors of metastatic N1 lymph nodes. RESULTS The median follow-up duration was 44.2 (6–135) months, recurrence occurred in 76 (39%) and 66 (34%) died. The 3- and 5-year disease-free survival rates and overall survival rates were 65 and 58%, and 89 and 72%, respectively. Univariate analysis identified being a never smoker, adenocarcinoma, pathological stage, hilar node metastasis, multistation metastasis, having four or more metastatic LNs and the lymph node ratio as factors predicting recurrence. Multivariate analysis revealed that adenocarcinoma, pathological stage III and multiple stations of metastatic lymph node were independent risk factors of recurrence. CONCLUSIONS Besides adenocarcinoma and pathological stage III, multistation metastasis was the single prognostic factor among various characteristics of metastatic N1 lymph nodes.