WCLC 2025 - Posters & ePosters-EP.06.79 Liquid Biopsy Shortens Time to Diagnosis and Treatment Selection: Primary Results From the International L1St Study

EP.06.79 Liquid Biopsy Shortens Time to Diagnosis and Treatment Selection: Primary Results From the International L1St Study

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The international L1st study (NCT05846594) evaluated the impact of liquid biopsy-based comprehensive genomic profiling using FoundationOne Liquid CDx (F1LCDx) on diagnostic and treatment timelines in patients with suspected advanced lung cancer. Traditional standard of care (SoC) diagnostic pathways, which rely primarily on tissue biopsies, often delay molecular testing and treatment decisions by weeks. This study compared F1LCDx liquid biopsy to SoC in two patient groups: basic workup (no prior tissue biopsy) and extended workup (prior tissue biopsy).<br /><br />By the study cutoff in October 2024, 257 participants were enrolled, with 159 undergoing basic workup and 98 extended. The median time to diagnosis using F1LCDx was significantly shorter than SoC: 14 days versus 35 days overall, with similar reductions in both basic and extended workup groups (p=0.0001). Time to treatment recommendation was also significantly faster with F1LCDx, with median times of 20 days versus 43 days for SoC (p=0.0001). Concordance between treatment recommendations based on liquid biopsy and SoC was 78%.<br /><br />Genomic alterations were detected in 82% of participants, with 62% harboring clinically actionable targets per ESMO ESCAT guidelines, including mutations in EGFR, KRAS, MET, ALK, and others. Notably, 16% of patients were assigned first-line targeted therapies based on F1LCDx results compared to 12% with SoC.<br /><br />The study concludes that liquid biopsy-based comprehensive genomic profiling can substantially shorten time to diagnosis and treatment recommendation compared to tissue-based SoC in advanced lung cancer. By enabling early molecular diagnostics before tissue collection, liquid biopsy streamlines clinical decision-making and supports timely initiation of targeted therapies, potentially improving outcomes. These findings support incorporating liquid biopsy into routine initial diagnostic workflows for advanced lung cancer, emphasizing its role in accelerating personalized cancer care.

Asset Subtitle

Fabrice Barlesi

Meta Tag

Speaker Fabrice Barlesi

Topic Pathology and Biomarkers

Keywords

Liquid biopsy

FoundationOne Liquid CDx

Advanced lung cancer

Comprehensive genomic profiling

Diagnostic timelines

Treatment recommendation

Tissue biopsy

Molecular testing

Targeted therapies

ESMO ESCAT guidelines