Novel bronchoscopy method for molecular profiling of lung cancer: Targeted washing technique: A prospective cohort study

Abstract

Abstract Background Efforts have been made to identify alternative samples to standard samples of tumor tissue or plasma for mutational analyses of patients with lung cancer. However, no other samples or techniques have replaced mutational analysis using standard samples. In this prospective study, we assessed a novel bronchoscopic method, the targeted washing technique, for the detection of EGFR mutations. Methods A 3.0-mm ultrathin bronchoscope was precisely navigated to the target lung lesion using virtual bronchoscopic navigation and fluoroscopy. Once the bronchoscope was placed in front of the target lung lesion, normal saline was administered for targeted washing. EGFR testing using targeted washing fluid (TWF) was compared with standard methods using plasma or tumor tissues. Results In 41 TWF samples, the T790M mutation was detected in 22%, 10%, and 29% of tissue, plasma, and TWF samples, respectively. The overall EGFR T790M detection rate in the tissue, plasma, or TWF samples was 37%, with TWF samples increasing the T790M mutation detection rate by up to 10%. The accuracy of T790M mutation detection using the TWF sample was 83% compared to that of standard samples. Four patients were found to have the EGFR T790M mutation only through EGFR testing using TWF, and repeated re-biopsies using either plasma or tissue confirmed the presence of the T790M mutation. Conclusion We demonstrated the clinical potential of targeted washing technique for molecular testing, which can be a good option to overcome spatial heterogeneity, low sensitivity of plasma samples, or technical limitations in collecting tumor tissues.