WCLC 2025 - Posters & ePosters-EP.06.81 Observational Study of Concordance Between Tissue-Based ODxTT CDx and In-House Plasma OPA Gene Analysis in NSCLC Patients

EP.06.81 Observational Study of Concordance Between Tissue-Based ODxTT CDx and In-House Plasma OPA Gene Analysis in NSCLC Patients

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This observational study conducted at Matsusaka Municipal Hospital Respiratory Center assessed the concordance between tissue-based genomic profiling using Oncomine Dx Target Test companion diagnostic (ODxTT CDx) and plasma-based Oncomine Precision Assay (OPA) in non-small cell lung cancer (NSCLC) patients. While tissue-based ODxTT CDx is the standard genomic testing method in Japan, limitations such as insufficient tumor tissue have driven interest in plasma-based assays, which are less invasive.<br /><br />The study included 51 NSCLC patients who underwent both ODxTT CDx and plasma OPA testing within 60 days between May 2022 and February 2025. The ODxTT CDx uses next-generation sequencing (NGS) to analyze multiple actionable genes from tumor tissue, whereas OPA, an NGS-based tool with broader gene coverage, assesses plasma samples. <br /><br />Key findings showed an overall concordance rate of 72.5% between the two methods across all genes tested. For therapeutic driver oncogenes (e.g., EGFR, ALK, ROS1), concordance improved to 84.3% with a high positive predictive value (PPV) of 95.7%, indicating strong agreement of plasma OPA positivity with tissue ODxTT CDx results. Negative predictive values (NPV) were lower, reflecting limitations in negative concordance. Concordance and PPV were notably higher in advanced-stage patients compared to early-stage, consistent with known increased circulating tumor DNA (ctDNA) detectability in advanced disease. Unexpectedly, adenocarcinoma samples showed higher concordance and PPV than squamous cell carcinoma, contrasting some prior reports and attributed to study limitations like small sample size.<br /><br />Overall, the study supports plasma-based OPA as a promising, less invasive complement to tissue testing for identifying actionable mutations in NSCLC, especially therapeutic driver genes. However, results highlight the need for larger prospective studies to further validate plasma testing performance across clinical stages and tumor histologies. The findings align with existing literature on ctDNA utility in advanced cancer and precision oncology applications.

Asset Subtitle

Kentaro Nakanishi

Meta Tag

Speaker Kentaro Nakanishi

Topic Pathology and Biomarkers

Keywords

non-small cell lung cancer

NSCLC

Oncomine Dx Target Test

ODxTT CDx

Oncomine Precision Assay

OPA

next-generation sequencing

NGS

plasma-based genomic profiling

tissue-based genomic profiling