Detection of comprehensive oncogenic driver alteration of non-small cell lung cancer from cytology specimens by multi-gene PCR panel.

Abstract

8579 Background: The analysis of the next-generation sequencing (NGS) panel test requires a sufficient amount of tissue specimens (TS), but the collection of tissue specimens can be sometimes challenging in clinical practice. Despite being easier and safer to collect than TS, cytology specimens (CS) are considered unsuitable for NGS due to the small number of tumor cells. The AmoyDx Pan Lung Cancer PCR Panel (AmoyDx), a multi-gene PCR panel that amplified mutation or fusion variants of 11 genes (EGFR, ALK, ROS1, RET, MET HER2, BRAF, KRAS, and NTRK1-3) by real-time PCR, can be performed with smaller amounts of nucleic acid than NGS, and CS may be suitable for multi-gene analysis using this panel. In this study, we evaluated the feasibility of multi-gene analysis using CS, and the concordance rate of gene alteration between CS and TS in non–small cell lung cancer (NSCLC). Methods: We enrolled consecutive NSCLC patients obtaining CS through bronchoscopy, including transbronchial brushing (TBB) and transbronchial needle aspiration (TBNA) from September 2020 to March 2023. These CS were preserved as frozen pellets. The difference in the amount of nucleic acid, the success rate and the concordance rate of gene alteration with AmoyDx were evaluated between CS and pared TS collected simultaneously with CS. Results: A total of 131 (Ad/Sq/NSCLC-NOS: 113/2/16) cases were enrolled in this study. Fifty-nine specimens were obtained through TBB and another 72 were obtained through TBNB. The median nucleic acid concentration (NanoDrop [ng/μL]) isolated from CS was comparable to that isolated from TS (DNA 114/99, p=0.96; RNA 36/27, p=0.63). However, the median DNA concentration in CS was significantly lower (80/102, p=0.01) in TBB samples, while in TBNA samples, it was higher (134/90, p=0.03). Almost all CS (99.2%,130/131) and TS (99.2%,130/131) were analyzed successfully with AmoyDx, with only one RNA analysis failure in each group. Among CS, 78 (60%) samples exhibit gene alteration, including EGFR/KRAS/BRAF/HER2/ALK/ROS1/MET/RET: 44/9/2/5/8/1/8/1, while 77 (59%); 44/9/2/6/6/1/8/1 in TS. The positive percent agreement, negative percent agreement, and overall percent agreement of CS using analysis compared with the results of TS using analysis were 99% (76/77), 96% (52/54), and 98% (128/131), respectively. Conclusions: CS exhibit an extremely high success rate for multi-gene analysis, with nucleic acid yield comparable to TS. Moreover, the concordance rate of gene alteration between CS and TS is also remarkably high. CS emerge as a viable alternative to TS for analyzing driver gene alteration in multi-gene PCR analysis.