Dividing EBUS-TBNA samples for simultaneous histopathological and molecular analyses in lung cancer patients

Background: Mediastinal lung cancer staging is preferably performed via endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). The assessment of an increasing number of predictive molecular markers for targeted therapy leads to time-delay. Dividing EBUS-TBNA samples allows earlier initiation of targeted therapy. However, it is unknown if this procedure diminishes accuracy and sensitivity of histopathologic and molecular analyses. Objectives: We evaluated accuracy and sensitivity of histopathologic and molecular analyses of divided EBUS-TBNA samples. Methods: EBUS-TBNA was performed in 88 patients with 249 enlarged lymph nodes. Negative or ambiguous histopathological results were confirmed by surgical means and clinical follow-up over 6 months. Samples were transferred onto glass slides, and then manually divided into two equivalent parts. One part was immediately put on dry ice and stored at -80°C before further molecular analyses, the other part was put into formalin before histopathological workup. The accuracy of the histopathological diagnosis and the suitability for molecular analyses were assessed. The amount of needle passes was recorded. Results: Division of EBUS-TBNA samples for simultaneous histopathological and molecular analyses was feasible in all cases . Lymph nodes were punctured an average of 3.18 times. Sensitivity and accuracy of the lymph node staging by EBUS-TBNA were 96.6% and 97.6%, respectively. A molecular test based on cytokeratin-19-mRNA concentration was feasible in 74.1%. Conclusion: Dividing EBUS-TBNA samples instead of taking additional samples provides high accuracy and sensitivity.