Cryobiopsy To Increase The Detection Rate Of Egrf-Mutations In Non-Small Cell Lung Cancer.

e20613 Background: Activating mutations in the epidermal growth factor receptor (EGFR) gene are pharmacological targets for EGFR tyrosine kinase inhibitors (TKI) in patients with advanced non-small-cell lung cancer (NSCLC) and targeted TKI therapy improves survival in comparison to conventional chemotherapy. This retrospective single center study evaluates the detection rate of mutated EGFR obtained by bronchoscopic cryobiopsy, in comparison to standard sampling techniques. Methods: A total of 420 specimens (03/2008-07/2014) with pathologically confirmed NSCLC and EGFR mutation status tested by Sanger sequencing (Exon 18-21) were studied. Samples obtained by bronchoscopic cryobiopsy were compared with those obtained by other biopsy techniques such as bronchoscopic forceps biopsies, fine needle aspiration, imaging guided transthoracic core needle biopsies and surgical procedures. Results: The cryobiopsy group and the non-cryobiopsy group did not differ regarding smoking history, age and gender. Bronchoscopic cryobiopsy detected activating EGFR mutations in 28 of 126 patients (22.2%) while non cryobiopsy techniques detected mutations in 45 of 294 patients (14.3%) respectively (p = 0.046). 108 cryobiopsies were performed in the central airways, 18 were done in the peripheral airways. There was a non significant higher EGFR mutation rate in bronchoscopic biopsies harvested in the lung periphery compared to the central airways (27% vs. 16,8%). Conclusions: Bronchoscopic cryobiopsy increased the detection rate of activating EGFR mutations in NSCLC compared to other tissue sampling techniques by far. This difference cannot only be explained by an imbalance of biopsy localization. Samples obtained by cryobiopsy might provide better material to detect mutations of EGRF. The higher rate of EGFR mutations in the cryobiopsy group suggests, that there might be false negative results with current sampling techniques and therefore may explain response to TKI of EGFR wild type declared NSCLC patients. As the detection of EGFR mutations is crucial for treatment strategy, cryobiopsy may improve the outcome of a substantial number of patients. A prospective trial comparing cryobiopsy versus forceps biopsy will be initiated