Predictive Factors for Node Metastasis in Patients With Clinical Stage I Non-Small Cell Lung Cancer

Background Accurate clinical staging of non-small cell lung cancer (NSCLC) is essential for developing a treatment plan and evaluating suitability for minimally invasive surgery. The aim of this study was to evaluate predictive factors for metastasis of N1 and N2 nodes in clinical stage I NSCLC. Methods Records of patients with clinical stage I NSCLC who had undergone pulmonary resection with systematic node dissection or node sampling between 2003 and 2011 were retrospectively reviewed. To identify predictive factors for node metastasis, univariate and multivariate logistic regression analyses were performed. Results Among the 770 patients in this study, the overall prevalence of node metastasis was 19.4%, which included 11.3% of N1 nodes and 8.1% of N2 nodes. Predictive factors for N1 node metastasis included male sex, current smoker, non-adenocarcinoma, solid consistency, centrally located tumor, clinical T stage, cytokeratin fragment 21-1 level, tumor size, maximum standardized uptake value of the mass, and ground-glass opacity proportion. Adenocarcinoma, solid consistency, clinical T stage, carcinoembryonic antigen level, tumor size, and ground-glass opacity proportion were identified as predictors for N2 node metastasis. Both tumor size and solid consistency were independent predictive values of N1 node and N2 node metastasis by multivariate analysis. Conclusions Among the patients with clinical stage I NSCLC, 19.4% of the patients showed unexpected node metastasis, and large size and solid consistency of the tumor were predictive factors of node metastasis in clinical stage I NSCLC. Preoperative staging should be performed more thoroughly to increase the accuracy of preoperative staging, especially in those who have the larger size and solid consistency of the tumor.