Risk factors for relapse of resectable pathologic N2 non small lung cancer and prediction model for time-to-progression

Background: Pathologic N2 non-small-cell lung cancer (NSCLC) was demonstrated with poor survival among literature. In this study, we retrospectively reviewed patients with pathologic N2 NSCLC and received anatomic resection (i.e. lobectomy) for further relapse risk factor analysis. The aim of this study is to identify the clinicopathologic factors related to relapse among resectable N2 NSCLC patients and to help clinicians in developing individualized follow up program and treatment plan.

Method: From January 2005 to July 2012, 90 diagnosed pathologic N2 NSCLC patients were enrolled into this study. We retrospectively reviewed medical records, image studies, and pathology reports to collect the patient clinico-pathologic factors.

Result: We identified that patients with visceral pleural invasion (p = 0.001) and skip metastases along mediastinal lymph node (p = 0.01) had a significant relationship to distant and disseminated metastases. Patients who had 2 or more risk factors for relapse demonstrated poor disease free survival than those who had less than 2 risk factors (p = 0.02). The number of involved metastatic area were significantly influential to the period of time-to-progression. The duration of time-to-progression was correlated with square of number of involved metastatic areas. (Pearson correlation coefficient = -0.29; p = 0.036).

Conclusion: Relapse risk factors of resectable pathologic N2 NSCLC patient after anatomic resection were visceral pleural invasion, skip mediastinal lymph node involvement, and the receipt of neoadjuvant therapy. The duration of time-to-progression was correlated with square of number of involved metastatic areas.