1. EBUS-TBNA reduces the number of mediastinoscopies for the staging of lung cancer with more than fifty percent Background Methods Results Conclusion Niels J.M. Claessens 1, Klaartje W. Maas 2, J.A. (Alain) Kummer 1, Franz M.N.H. Schramel 1 1 Sint Antonius Hospital, Nieuwegein, The Netherlands 2 Haaglanden Medical Center, The Hague, The Netherlands Lung cancer is one of the most common malignancies worldwide. At the time of initial diagnosis locoregional metastasis are present in 22% and distant metastasis in 55% of cases. Treatment is guided by the stage of disease and therefore accuracy in staging is of great importance. Endobronchial ultrasound with transbronchial needle aspiration (EBUS- TBNA) is a relatively new minimally invasive technique for the sampling mediastinal lymph nodes. In certain circumstances mediastinoscopy might be avoided by the use of EBUS-TBNA. A retrospective single center cohort study was performed in the Sint Antonius Hospital in Nieuwegein, The Netherlands. The study period was September 2008 until January 2011. Patients that were suspected of having lung cancer were analysed according to current standing guidelines. Patients were included if invasive staging of the mediastinum was indicated and EBUS-TBNA was performed. If metastatic tumour cells were found in mediastinal lymph node aspirates the procedure was considered to be diagnostic and there was no indication for additional mediastinoscopy. If no metastatic tumour cells were found confirmation mediastinoscopy or endoscopic ultrasonography with fine needle aspiration (EUS-FNA) was indicated. Considering the relatively large number of patients in whom no confirmation testing of the cytologic results of EBUS-TBNA was performed, we calculated diagnostic yield for two extreme scenario’s to be able to give a range for sensitivity and negative predictive value. During the study period EBUS-TBNA was performed on 77 patients in our hospital for mediastinal staging in lung cancer. In 39 of 77 patients (51%) mediastinal lymph node metastasis were detected by EBUS-TBNA and mediastinoscopy was avoided. In 9 of 38 patients (24%) with benign cytology on EBUS-TBNA or a non-diagnostic procedure confirmation mediastinoscopy or EUS-FNA revealed mediastinal lymph node metastasis. In 13 of these 38 patients no cytologic or histologic confirmation testing was performed. Diagnostic yield was calculated for the two extreme scenario’s. Range of sensitivity and negative predictive value were 64-81% and 42-76% respectively. In just over 50% of patients with lung cancer in whom invasive staging of the mediastinum was indicated mediastinoscopy can be avoided when EBUS-TBNA is used. In this study the sensitivity and negative predictive value were lower than reported in previous studies. EBUS-TBNA can therefor not fully replace cercival mediastinoscopy for invasive staging of the mediastinum in lung cancer patients. Both techniques should be seen as complimentary but EBUS-TBNA is the procedure of first choice. Objectives To determine the diagnostic yield of EBUS- TBNA and calculate the reduction in number of mediastinoscopies when EBUS- TBNA is used as initial invasive staging modality of the mediastinal lymph nodes in lung cancer patients. Total EBUS-TBNA for staging of lung carcinoma 77 Malignancy 39/77 (51%) Squamous cell carcinoma 10/39 (26%) Adenocarcinoma 8/39 (21%) Large cell lung carcinoma 12/39 (31%) Small cell lung carcinoma 9/39 (23%) Lymphoid tissue 26/77 (34%) Additional mediastinoscopy 21/26 (81%) Benign lymphoid tissue 16/26 (62%) Squamous cell carcinoma 1/26 (4%) Adenocarcinoma 4/26 (15%) No additional diagnostic test 5/26 (19%) Granuloma 1/77 (1,3%) Additional mediastinoscopy 1/1 (100%) Adenocarcinoma 1/1 (100%) Non-adequate cytologic material 11/77 (14%) Additional mediastinoscopy 2/11 (18%) Squamous cell carcinoma 1/2 (50%) Large cell lung carcinoma 1/2 (50%) Additional EUS-FNA 1/11 (9%) Adenocarcinoma 1/1 (100%) No additional diagnostic test 8/11 (73%) Diagnostic flow-chart and overview of pathologic anatomic results of cytologic material gathered through EBUS-TBNA and EUS-FNA and histologic material gathered through mediastinoscopy from September 2008 until January 2011 in the St Antonius Hospital, Nieuwegein, The Netherlands. Contact n.claessens@antoniusziekenhuis.nl