Correlation between Characteristics of Lymph Node Metastasis and Prognosis of N1-N2 Stage Non-small Cell Lung Cancer

Abstract

Objective: Patients with non-small cell lung cancer have prognostic heterogeneity, chief prognosis factor of them lymph node metastasis. Our study aimed to evaluate the correlation between lymph node ratio, the number of involved lymph node stations and skip-N2 metastasis and prognosis of N1-N2 stage non-small cell lung cancer. Methods: A total of 374 patients with N1 and N2 stage non-small cell lung cancer were retrospectively analyzed who underwent radical resection at the Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University from January 2012 to December 2019. Cox regression was conducted to identify the independent prognosis factors for N1-N2 stage non-small cell lung cancer. Survival curves were plotted by Kaplan-Meier method. Subgroup analyses were performed regarding proposals for the revision of the N descriptors in the 8th edition of the TNM classification. Results: Multivariate analysis of Cox regression model confirmed that smoking history, multiple-station lymph node metastasis and lymph node rate were independent prognosis factors for disease-free survival. Male, smoking history, multiple-station lymph node metastasis, lymph node ratio, adjuvant chemotherapy and targeted therapy were independent prognosis factors for overall survival. The 5-year overall survival was 57.4% in skip N2 group, while being 65.1% in N1 group (P=0.138) and 36.2% in the non-skip N2 group (P=0.007). Conclusion: Combined with lymph node ratio, the number of involved lymph node stations and skip metastasis, we can effectively predict the inter-subgroup survival difference.