Differentiating metastatic lymph nodes in lung cancer patients based on endobronchial ultrasonography features

The aim of this study was to identify easy and relatively effective ultrasound criteria for metastatic mediastinal lymph node prediction.

A retrospective chart review of patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) from March 2014 to September 2016 was performed. We used the following EBUS sonographic features for metastatic lymph node prediction: 1) length of the short axis, 2) shape, 3) margin, 4) echogenicity, 5) central hilar structure, and 6) coagulation necrosis sign. These sonographic findings were compared with the final pathology results or clinical follow-up.

A total of 227 lymph nodes were retrospectively evaluated in 133 lung cancer patients; 72% of the lymph nodes had been proven to be malignant metastasis. Logistic regression analysis revealed that the length of the short axis, shape, margin, and echogenicity were independent predictive factors for metastasis. We developed a sum score based on these four sonographic features. A larger sum score trended toward a greater possibility of malignancy. If all four predictive factors were preserved, the diagnostic accuracy, the value of the specificity and the positive predictive value of the sonographic feature would be higher than 90%.

The sonographic features of EBUS are valuable tools in predicting metastatic lymph nodes in lung cancer patients.