Feasibility of EGFR mutation testing on EBUS-TBNA and bronchial biopsy samples obtained during routine practice

Introduction. Approximately 80% of NSCLC present with advanced disease, in whom the diagnosis is often based on small samples obtained during bronchoscopy. Aims. We aimed to evaluate the performance of bronchoscopic small tissue samples: (1) the percentage of tumour cells and quantity of DNA extracted; (2) the performance of EGFR mutation testing; (3) their feasibility compared to surgical samples. Methods. Between Sep 2010 and Dec 2012, we screened advanced stage non-squamous histology for EGFR mutations using Therascreen. All diagnostic bronchial biopsies (n=130; 4 biopsies per patient) and EBUS-TBNA samples (n=81; 4 needle aspirations brought in cell block), as well as surgical samples (n=67) were retrieved. Results. The median percentage tumour cells and quantity of DNA extracted was significantly higher in surgical vs bronchoscopic samples (80% vs 30% and 2.3µg vs 1.6μg, P Although 25% of bronchoscopic samples had 35) were observed in 1%. Conclusions. Bronchoscopic samples result in accurate EGFR mutation analysis in routine practice, provided a sufficient samples are taken.