Value of the Metastatic Lymph Node Ratio for Predicting the Prognosis of Non-Small-Cell Lung Cancer Patients

The aim of this study was to investigate the relation between the metastatic lymph node ratio (LNR) and the prognosis of non-small-cell lung cancer (NSCLC). A total of 301 patients with N1 or N2 NSCLC who underwent complete pulmonary resection were analyzed retrospectively. The correlations between the LNR and clinical and pathologic data were analyzed using chi(2) test analysis. The prognostic value of the LNR was calculated by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. The risk groups were classified by a combination of the LNR and pN stage. The LNR was correlated with age, smoking status, pathologic type, subcarinal lymph node, clinical staging, N stage (P < 0.05), and the number of positive lymph nodes and positive lymph node stations (P < 0.0001). In the univariate analysis, the LNR played an important role in predicting overall survival (OS) (P < 0.0001) and disease-free survival (P < 0.0001) by Kaplan-Meier survival analysis. In the multivariate analysis, high LNR (> 18%) was an independent poor prognostic factor for OS [hazard ratio (HR) 2.5034, 95% confidence interval (CI) 1.6096-3.8933, P < 0.0001] and DFS (HR 1.9023, 95% CI 1.2465-2.9031, P = 0.0031). Stratification into high-, medium-, and low-risk groups-based on high-risk factors (LNR > 18%, N2) intermediate-risk factors (LNR > 18%, N1 or LNR < 18%, N2), and low-risk factors (LNR < 18%, N1)-could efficiently predicted outcomes (P < 0.0001) of patients with lymph node-positive NSCLC. The combination of the LNR and pN status provides a valuable help with prognosis. However, these results must be evaluated further in a large prospective randomized clinical trial.