The feasibility of using small biopsy samples from lung cancer for targeted next-generation sequencing.

Abstract

e20584 Background: As the genomic based personalized medicine has been advanced, biomarker analysis using targeted next-generation sequencing (NGS) becomes crucial diagnostic approach for treatment of lung cancer. Most patients of lung cancer are diagnosed on small biopsy specimen, but the feasibility of the small tissue samples for targeted NGS has not been evaluated. We aimed to investigate the feasibility of using small tissue samples of lung cancer for targeted NGS. Methods: The medical records of the patients who underwent biopsy and targeted NGS were reviewed. Two types of panel for targeted NGS were used which were AmpliSeq Cancer Hotspot panel v2 and Oncomine Focus Assay. Results: A total of 603 biopsy specimens of lung cancer were analyzed from April 2014 to October 2016. The sites of biopsy were lung or bronchus (51.2%), lymph node (26.2%), Pleura (2.3%), liver (2.5%), Brain (1.7%) and the others (adrenal gland, bone, muscle, spleen, stomach, thymus). Percutaneous transthoracic core needle biopsy (PTCNB) was most frequently used method for acquisition of tissue (24.9%). The other methods of biopsy were bronchoscopy (14.4%), endobronchial ultrasound (EBUS, 23.8%), Video-assisted transthoracic surgery (VATS, 9.9%) and so on. The types of tissue samples were formalin-fixed, paraffin-embedded (FFPE, 80.6%) and fresh tissue (19.4%). All of these samples, 398 cases (66.0%) were successfully analyzed using targeted, NGS. In 34% of analysis failure cases, 23.5% were not adequate for DNA or RNA extraction and 10.5% had amount not to be enough. On multivariate analysis, PTCNB was more likely to fail than other methods of biopsy such as bronchoscopy, EBUS (HR 2.31, 95% CI 1.4-3.8, p = 0.001). Conclusions: The biopsy of lung cancer for targeted NGS was taken from a variety of sites via different methods, and the type of tissue samples was mostly FFPE. Considering the yield of our study, small biopsy specimens could be used to investigate genomic characteristics of lung cancer via targeted NGS.