Tumor characteristics of lung cancer in predicting axillary lymph node metastases

Objective: In lung cancer, axillary lymph node metastases (ALM) are rare, and according to the 8th grading system, it is classified as M1b disease. The aim of this study is to evaluate 1 ) the presence of ALM and2) the effect of the primary tumors characteristics on the development of ALM. Methods: We performed a descriptive cross-sectional study, with retrospective revision, to identify ALM. Results: There were 157 patients included in this analysis: ALM (63 patients) and control group (94 patients). The presence of extrathoracic lymph node, contralateral pulmonary parenchymal and distant metastasis and all SUVmax values were significantly higher in the study group versus the control group (P< 0.05). The SUVmax value of the primary tumor was not a predictor of ALM. According to the primary histopathologic diagnosis, small cell lung cancer was found to cause ALM development 3.4 times as much as squamous cancer (SQC) (OR: 3.40 [95% CI 1.3-10.20], P= 0.029) and adenocarcinoma group was found to cause ALM development 4 times as much as SQC (OR: 4.02 [95% CI 1.73-9.34], P= 0.001). The likelihood of developing ALM was significantly higher in tumors located in the central and upper lobe versus the lower lobe. Conclusion: The finding of ALM on PET/CT images, the necessity of histopathologic confirmation is determined according to the results of primary tumor localization, primary tumor histopathology, M stage on PET/CT imaging, localization of ALM according to primary tumor, and N stage on PET/CT imaging. (C) 2018 Sociedad Espanola de Medicina Nuclear e Imagen Molecular. Published by Elsevier Espana, S.L.U. All rights reserved.