Clinical Value Of EBUS-TBNA In Evaluating Intrathoracic Lymph Node Metastasis In Patients With Primary Lung Cancer

Objective: Endobronchial ultrasound-guided transbronchial needle aspiration(EBUS-TBNA)is a diagnostic method aiming to evaluate suspicious lymph node metastasis in patients with primary lung cancer because of such advantages as minimal invasion,easy-to-repeat,mild postoperative complication,as well as its sensitivity and specificity similar to mediastinoscopy.However,it still cannot replace mediastinoscopy totally.The objective of this study was to discuss the diagnostic value of EBUS-TBNA for evaluating metastases of mediastinal and hilar lymph nodes in patients with primary lung cancer and further analyze its optimum range of application.Methods: 373 patients who were preliminarily diagnosed of primarily lung cancer with enlargement of hilar and mediastinal lymph nodes(long diameter>1cm)by chest CT plain scan and enhanced scan and/or PET-CT from January 2012 to December 2018 in our hospital were analyzed retrospectively.Standardized EBUS-TBNA was performed to obtain the lymph node cells or tissues for pathological examination.Those patients whose pathological results were negative further received mediastinoscopy or thoracoscope or other operations to confirm the pathological diagnosis.The clinical data of these patients were analyzed to evaluate its clinical diagnostic value and further analyze its optimum range of application for the diagnosis of metastases of mediastinal and hilar lymph nodes in patients with primary lung cancer.Results: A total of 373 patients received standardized EBUS-TBNA,and 401 lymph node samples were collected from different areas of the body.The result of pathological examination confirmed 354 malignant lymph nodes.In the rest 47 lymph nodes,a total of 15 pulmonary malignant lymph nodes were finally confirmed by further operation.Among them,metastatic lymph nodes from right lung are relatively common.The number of metastatic lymph nodes in group 7 and group 4R exceeded 50% of the total number.The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of EBUS-TBNA for hilar and mediastinal lymph nodes with a long diameter of >1cm were 95.94%,100%,96.24%,100% and 66.67%.After subgroup analysis,the sensitivity and accuracy of EBUS-TBNA for mediastinal lymph nodes were higher than that for hilar lymph nodes,the negative prediction rate for mediastinal lymph nodes was higher than that for hilar lymph nodes,and the sensitivity and accuracy of EBUS-TBNA for patients with small cell lung cancer(SCLC)were higher than that for patients with non-small cell lung cancer(NSCLC).All the patients receiving EBUS-TBNA showed good tolerance,without causing severe complications.For patients with NSCLC,the factors associated with false negativity were CEA,CYFRA21-1 and size of lymph node,and size of lymph node was an independent influencing factor.CONCLUSION: EBUS-TBNA is a safe,effective,convenient and minimally invasive diagnostic technique.It shows high sensitivity and accuracy for the diagnosis of primary lung cancer with metastases of hilar and mediastinal lymph nodes.EBUS-TBNA has high sensitivity and accuracy for patients with SCLC and mediastinal lymph nodes.It is expected to replace mediastinoscopy and become the golden standard for the diagnosis of primary lung cancer with metastases of hilar and mediastinal lymph nodes.For patients with NSCLC,EBUS-TBNA cannot replace mediastinoscopy and its false negative rate is significantly increased.The factors associated with false negativity are CEA,CYFRA21-1,and size of lymph node,which is an independent influencing factor.It is recommended that even if the pathological examination of EBUS-TBNA for patient with lymph nodes of <1.95 cm turns out to be negative,it is still necessary to perform secondary biopsy or direct mediastinoscopy or thoracoscope to confirm the pathological diagnosis.