Lymph node ratio as a prognostic factor in patients with pathological N2 non-small cell lung cancer

BACKGROUND: The aim of this study was to investigate whether the lymph node ratio (LNR) was associated with the prognosis of patients, who underwent surgery for pathological N2 non-small cell lung cancer (NSCLC). METHODS: A total of 182 patients were diagnosed with pathological N2 disease and underwent complete resection surgeries with systematic lymphadenectomies. We counted the number of positives and removed lymph nodes to calculate a ratio between them (LNR). We also investigated the association between skip mediastinal lymph node metastasis and survival. RESULTS: Univariate analysis of survival in patients with N2 NSCLC showed that the T factor, clinical N factor, and LNR were significant prognostic factors. Multivariate analyses showed that the clinical N stage and LNR were significant independent prognostic factors for patients with pathological N2 NSCLC. Patients with a clinical lymph node status of 0 (cN0) and LNR ≤0.22 showed a significantly higher survival rate than patients with a cN1-2 and LNR ≥0.22 and 5-year survival rates were 47.1 and 10.3%, respectively (p < 0.0001). CONCLUSIONS: LNR is an important prognostic factor for poor outcome following surgery in patients with N2 disease. The combination of the LNR and cN status provides a valuable prognostic tool.