RESUMEN
<p><b>OBJECTIVE</b>To investigate the prognosis of patients with N1 non-small cell lung cancer, and to compare the clinicopathological features and survival between patients with unexpected N1 (cN0-pN1) and expected N1 disease (cN1-pN1) after operation for non-small cell lung cancer.</p><p><b>METHODS</b>This study retrospectively reviewed and analyzed the medical records of 183 patients who underwent surgery and pathologically diagnosed with N1 non-small cell lung cancer between January 2006 and December 2010. Among them, 78 patients had negative findings before surgery (cN0-pN1 group), and 105 patients had positive findings before surgery (cN1-pN1 group). The clinicopathological features, median survival time and 5-year survival rates between the two groups were analyzed.</p><p><b>RESULTS</b>Patients in the cN1-pN1 group had greater pathologic T stage, larger tumors, greater number and stations of positive N1 lymph nodes, and greater percentage of pneumonectomy than those in the cN0-pN1 group (P < 0.05). For the patients with cN0-pN1, the MST was 47.0 months and the 1-, 3-, and 5-year OS were 85.9%, 57.4%, and 42.5%, respectively. For the patients with cN1-pN1, the MST was 30.0 months and the 1-, 3-, and 5-year OS were 74.3%, 44.6%, and 28.8%, respectively. There were significant differences in survival between the two groups (P < 0.05). The locoregional recurrence rate of cN0-pN1 group was lower than in the cN1-pN1group (P < 0.05). The multivariate analysis showed that T staging and N staging before surgery, lymph node metastasis to multiple N1 stations and adjuvant chemotherapy were independent prognostic factors.</p><p><b>CONCLUSIONS</b>Different clinical features of N1 non-small cell lung cancer has certain heterogeneity. Patients with unexpected N1 disease show better survival and lower locoregional recurrence rate than did those with expected N1 disease.</p>