Predictive Risk Factors For Lymph Node Metastasis In Clinical Early Stage Non-Small Cell Lung Cancer Patients

Objective:Accurate clinical stage affects the therapeutic modality and prognosis of non-small cell lung cancer (NSCLC) patients, all lung tumors have been treated regardless of tumor location, we aimed to identify predictive risk factors for N2metastasis in clinical stage IA NSCLC patients and the differences in the metastatic pathway to mediastinum between lung cancers originating from different lobes, so as to optimize the surgical candidates, and the extent of lymph node dissection.Methods:We retrospectively evaluated clinical stage IA NSCLC patients who underwent surgical pulmonary resection with systematic lymphadenectomy from January2011to January2013. Univariate and multivariate logistic regression analyses were performed to identify risk factors for N2metastasis. For the significant factors, optimal cutoff points were determined with a receiver operating characteristic (ROC) analysis and Youden’s index. The relationship between metastatic lymph node station and tumor location was also analyzed. Results:Among the552patients included in this study, a total of109patients (19.0%) were with N2metastasis. Female sex(OR=2.722, p=0.001), tumor size on preoperative CT findings(OR:1.875, p=0.002), preoperative serum CEA level (OR=1.049, p-0.006) were identified as risk factors for N2metastasis by multivariate logistic regression analysis. The optimal cutoff determined by ROC analysis and Youden’s index for sex, tumor size, serum CEA level were female,1.8cm,5.2ng/ml respectively. The right upper lobe originated tumors showed a significantly higher incidence of lower paratracheal node metastasis than those from right lower lobes (76.7%vs32.0, p<0.001), and a lower incidence of subcarinal node metastasis than tumors from right lower lobes (23.3%vs64.0%, p=0.002). Tumors of left upper lobes showed a significantly higher incidence of aortic node metastasis than tumors of left lower lobes (90.9%vs62.5%, p=0.003), but a significantly lower incidence of subcarinal node metastasis (0%vs56.3%, p<0.001).Conclusions:Clinical stage IA NSCLC patients were with high incidence of N2metastasis, systematic lymph node dissection or sampling would be mandatory for accurate staging of these tumors. Meanwhile, preoperative mediastinal staging should be more thoroughly and carefully in clinical stage IA NSCLC patients with these predictive risk factors to avoid improper treatment. Tumors of different lobes have different metastatic pathway to the mediastinum. Objective:Accurate clinical staging of non-small cell lung cancer (NSCLC) is essential for developing the optimal treatment strategy. This study aimed to determine the predictive risk factors for lymph node metastasis including both N1and N2metastasis in clinical TlaN0NSCLC patients.Methods:We retrospectively evaluated clinical TlaNOMO NSCLC patients without radiologic evidence of lymph node metastasis who underwent surgical pulmonary resection with systematic mediastinal node dissection or sampling at First affiliated hospital of Zhejiang University from January2011to June2013. To identify predictive factors for node metastasis, univariate and multivariate logistic regression analyses were performed.Results:Pathologically positive lymph nodes were found in16.2%(51/315) patients. Positive N1nodes were found in12.4%(39/315) patients, positive N2nodes were identified in13.0%(41/315) patients.9.2%(29/315) patients had both positive N1and N2nodes,3.8%(12/315) patients had nodal skip metastasis. Variables of preoperative radiographic tumor size, non-upper lobes located tumors, high CEA level, and micropapillary predominant adenocarcinoma were identified as predictors for positive N1or N2nodes multivariate analysis.Conclusions:Pathologically positive lymph nodes were common in small sized NSCLC patients with clinical negative lymph nodes. Preoperative staging should be performed more thoroughly to increase the accuracy of preoperative staging, especially in those who have the larger size, non-upper lobe located, high CEA level and micropapillary predominant adenocarcinomas.