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 pre-operative 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. (C) 2011 Elsevier Ireland Ltd. All rights reserved.