The effect of the number of dissected lymph nodes on survival in patients operated on for T1a-T2a N0 non-small cell lung cancer

Background: This study aims to investigate the effect of the number of dissected lymph nodes on survival in patients operated on for T-1a-T-2a N-0 non-small cell lung cancer. Methods: The medical records and follow-up data of patients operated on for non-small cell lung cancer between January 2005 and December 2009 were analyzed retrospectively. One hundred and forty-one patients (128 males, 13 females; mean age 63 +/- 8.7 years; range 37 to 82 years) who did not receive neoadjuvant treatment, with pathological stage of T1aN0M0, T1bN0M0, and T2aN0M0 (stage I according to seventh edition of tumor-node-metastasis classification of malignant tumors), and who were performed lobectomy or pneumonectomy and mediastinal lymph node dissection were included in this study. The significance between the total number of dissected lymph nodes from both N-1 and N-2 stations and the survival of the patients were evaluated. The patients were divided into two groups: Group A included the patients having less than nine lymph nodes dissected, whereas group B included the patients with nine or more dissected nodes. Survival rates of the two groups were compared. Results: The survival rate was lower in group A compared to that of group B and the difference was statistically significant. The multivariate Cox regression analysis demonstrated that the number of dissected lymph nodes (in addition to age, gender, T stage, type of resection, and histopathologic subtype) was an independent prognostic factor. Conclusion: The number of lymph nodes dissected effects survival in non-small cell lung cancer in patients with stage T-1a-T-2 N-0. Surgeons should make an effort to dissect as many lymph nodes as possible during lung cancer surgery.