Feasibility of transbronchial brushing cytology specimens for next generation sequencing in peripheral lung cancer

Lung Cancer
30/10/2020

Cancer Sci. 2020 Oct 30. doi: 10.1111/cas.14714. Online ahead of print.

ABSTRACT

Next generation sequencing (NGS) enables the diagnosis of large numbers of gene aberrations during one examination, and precision medicine has developed in patients with advanced non-small cell lung cancer (NSCLC). However, peripheral lung lesions account for the majority of advanced lung cancers, especially lung adenocarcinoma. In these cases, it is difficult to obtain tissue samples which contain sufficient tumor cells by transbronchial biopsy (TBB) with forceps. Even when the target lesions


are quite small, bronchial brushing can obtain enough tumor cells by endobronchial ultrasonography using guide sheath (EBUS-GS). In this study, we investigate the feasibility of bronchial brushing cytology specimens obtained by EBUS-GS-TBB, to evaluate the correlation between the success rate of NGS and extracted DNA/RNA yields according to biopsy method. We prospectively collected 222 tumor samples obtained from patients with advanced lung cancer. All patients were enrolled in a prospective nationwide genomic screening project for lung cancer (LC-SCRUM-Japan/Asia). Genomic data were obtained from the clinico-genomic database of LC-SCRUM-Japan/Asia. Extraction yields of DNA/RNA from samples obtained by EBUS-GS-TBB were relatively lower than tissue samples. The success rate of DNA sequencing for EBUS-GS-TBB was 97.9%, and with no significant differences between biopsy method. The success rate of RNA sequencing for EBUS-GS-TBB was 80.4%, which was relatively lower than by surgical biopsy samples (P=0.069). However, some rare oncogenic driver aberrations were detected from these specimens. This study demonstrated that cytology samples obtained by transbronchial brushing with EBUS-GS-TBB were feasible for NGS analysis.