ObjectiveTo explore prognostic factors of non-small cell lung cancer(NSCLC)patients with preoperative clinical N0 staging but unexpected postoperative pathological N2 staging (cN0-pN2). MethodsClinical data of NSCLC patients with cN0-pN2 after radical lung cancer resection in Huashan Hospital Affiliated to Fudan University from January 2006 to December 2010 were retrospectively analyzed. Survival information was collected through followup, and follow-up expired on December 31, 2012. Prognostic factors of NSCLC patients with cN0-pN2 were analyzed using Cox proportional-hazard regression. ResultsA total of 263 patients were enrolled in this study. The followup rate was 91.63%. Overall 1-year, 3-year and 5-year survival rate was 94.6%, 55.2% and 26.3%, respectively. Videoassisted thoracoscopic surgery (VATS, P=0.017, RR=0.659, 95%CI 0.469-0.927), multiple stations of mediastinal lymph node metastases (P=0.003, RR=1.605, 95%CI 1.180-2.183), no adjuvant chemotherapy(P=0.012, RR=1.576, 95%CI 1.105-2.246) were independent predictive factors for NSCLC patients with cN0-pN2. For patients with single station N2, median survival after VATS was significantly longer than that after open thoracotomy (48.55 months vs. 37.34 months, P=0.018). For patients with multiple stations of mediastinal lymph node metastases, median survival without any adjuvant chemotherapy was significantly shorter than that after adjuvant chemotherapy (20.32 months vs. 31.55 months, P=0.001). ConclusionPrognosis of NSCLC patients with cN0-pN2 is related to operational methods, adjuvant chemotherapy and station number of mediastinal lymph node metastasis. Patients with single station of mediastinal lymph node metastasis are more likely to benefit from VATS while patients with multiple stations of mediastinal lymph node metastases are more likely to benefit from adjuvant chemotherapy.