Preoperative lymphocyte count is an independent prognostic factor in node-negative non-small cell lung cancer

A number of prognostic factors have been reported in non-small cell lung cancer (NSCLC). Although lymph node metastasis is the most poorly predictive value in completely resected NSCLC, a significant number of patients have a fatal recurrence even in node-negative curative NSCLC. Recently inflammatory response has been shown as a predictive value in NSCLC. Neutrophils and lymphocytes play an important role in cancer immune response. In this study, we retrospectively examined the impact of preoperative peripheral neutrophil and lymphocyte counts on survival, and investigated the relationships of these factors to clinicopathological factors in node-negative NSCLC. A total 237 patients were evaluated. When the cut-off value of neutrophil count was 4500 mm(-3) with a maximum log-rank statistical value, overall 5-year survival rates were 79.7% for the low-neutrophil-count group and 69.5% for the high-neutrophil-count group (P=0.04). When the cut-off value of lymphocyte count was 1900 mm(-3) with a maximum log-rank statistical value, overall survival rates were 67.9% for the low-lymphocyte group and 87.7% for the high-lymphocyte group (P<0.001). High-neutrophil-counts were associated with tumor size (P=0.002) and pleural invasion (P<0.001). Low-lymphocyte-counts were correlated with vascular invasion (P=0.018) and recurrence of NSCLC (P=0.01). Multivariate analysis showed that the lymphocyte count was an independent prognostic factor (hazard ratio: 3.842; 95% confidence interval: 1.827-8.078; P<0.001), but the neutrophil count was not (P=0.185). We conclude that a peripheral lymphocyte count, which is associated with vascular invasion, is an independent prognostic factor in node-negative NCSLC.