A comparative analysis of next-generation sequencing based on plasma cfDNA and tumor tissue DNA in patients with advanced lung cancer

e21021 Background: Although liquid biopsy based on plasma cell-free DNA (cfDNA) provides a non-invasive detection method for cancer patients, tissue biopsy is still the gold standard for molecular subtyping. The concordance of these two techniques has been evaluated in certain cohorts. The comparison of plasma cfDNA and tissue DNA NGS ina large Chinese cancer cohort is yet to be analyzed. Methods: We retrospectively reviewed HaploX's genomic sequencing data from July 2021 to December 2022 to assess the concordance between plasma cfDNA and cancer tissue DNA. A total of 589 advanced lung cancer patients with matched tissue and plasma sample were included in the study. Tissue and peripheral blood was collected at the same time during surgical operation or biopsy. Tissue DNA and plasma cfDNA were isolated and prepared for the NGS with commercially available kits. The positive percent agreement (PPA) between plasma cfDNA sequencing and tissue sequencing, the negative percent agreement (NPA), positive predictive value (PPV), negative predictive value (NPV), and overall percent agreement (OPA) were calculated and compared. Results: The positive percent agreement (PPA) of plasma cfDNA sequencing compared with tissue sequencing were 78% (EGFR, 82%; KRAS, 71%; HER2 mutation, 76%; BRAF V600E mutation, 75%; ALK fusion, 74%; RET fusion, 60%; ROS1 fusion,33.3%; MET exon14 skipping, 50%). EGFR mutations included EGFR p.L858R,19del, p.C797S, p.L861Q, p.T790M, KRAS mutations included p.G12X and p.Q61X.， HER2 mutations included gain-of-function mutations；NPA was 92.4%，PPV was 93.8%，NPV was 74.4%，OPA was 84%. Conclusions: The positive mutation detection consistency of plasma cfDNA sequencing and tissue sequencing in advanced lung cancer patients is 78%, indicating that liquid biopsy based on plasma cfDNA is reliable in most advanced lung cancer patients, but there are some limitations in gene fusion and MET exon 14 jumping detection. Liquid biopsy based on plasma cfDNA can meet most clinical genomic testing needs in general, especially when tissue is not available, but physicians need to be more cautious with negative results. Keywords: Liquid biopsy, Next-generation sequencing (NGS), Concordance Analysis, Lung Cancer.