Study On Endobronchial Ultrasound-guided Transbronchial Needle Aspiration (EBUS-TBNA) In Qualitative Diagnosis Of Mediastinal Lesions

[Objectives] Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) which has a large amount of advantages such as easy manipulation, minimal invasion and repeatability is a newly emerged option for diagnosis of mediastinal lymphadenopathy and has been widely applied clinically. A lot of studies showed that EBUS-TBNA had good sensitivity and specificity in diagnosing mediastinal lymph nodes metastasis of malignant tumors, which was even superior to other common examination. The purpose of the current study was to evaluate parameters such as accuracy of EBUS-TBNA in qualitative diagnosis of mediastinal lesions and to discuss its value, safety and optimal indication. Whether EBUS-TBNA can replace mediastinal lymphadenopathy was also discussed further.[Materials and methods] Between April 2009 to February 2010,123 patients with mediastinal lesions in Fudan University Shanghai Cancer Center were included in this prospective study. EBUS-TBNA was performed in all cases. The final diagnosis was confirmed by cytology, surgical results, and/or clinical follow-up for at least 6 months. We analyzed the accuracy, safety, sensitivity, specificity, positive and negative predictive value of EBUS-TBNA in diagnosis of mediastinal lesions according to the final diagnosis. The accuracy, safety, sensitivity, specificity, positive and negative predictive value of EBUS-TBNA for diagnosis of common diseases such as epithelial tumors, lymphoma and granulomatous inflammation was also assessed further and evaluated its value and the optimal indication.[Results] All 123 patients were received the water-filled balloon puncture method. EBUS-TBNA was successfully performed to obtain samples from 286 stations of lymph nodes (2.33 stations/per patient). The mean period of each puncture of every station was 4(3-55)min. The mean puncture depth was 25mm. The puncture success rate was 100%. The procedure was uneventful without complications. The postoperative stay length in hospital was 1-20 days. The mean stay length was one day. Final diagnosis indicated that there were 83 positive and 40 negative patients. EBUS-TBNA had a sensitivity of 95.18%, specificity of 100.00%, positive predictive value of 100.00%, negative predictive value of 90.91%, and overall accuracy of 96.75%. For diagnosis of the epithelial cancer, EBUS-TBNA had an accuracy of 98.81%, sensitivity of 98.75%, specificity of 100.00%, positive predictive value of 100.00%, negative predictive value of 80.00%. EBUS-TBNA failed to reveal three lymphomas. For diagnosis of benign mediastinal diseases, EBUS-TBNA had a diagnosis rate of 47.22% which had a confirmed clinical application value. EGFR mutation was detected in 13 EBUS-TBNA biopsy samples which were confirmed adenocarcinoma on cytological level. The mutation rate was 30.77%. And immunohistochemical detection was performed in 10 samples. The successful rate was 90.00%.[Conclusions] EBUS-TBNA can take the place of mediastinoscopy as a superior choice for diagnosis of epithelial tumors. EBUS-TBNA can not replace mediastinoscopy but be a promising tool for diagnosis of benign mediastinal diseases including sarcoidosis. For special diseases such as lymphoma, mediastinoscopy cannot be replaced. However, EBUS-TBNA can be a potentially favorite choice for early stage screening. Decrease of the false negative rate of EBUS-TBNA and immunohistochemical and molecular biological research of EBUS-TBNA samples are of great importance in the future.