Liquid Biopsy Versus Tissue Biopsy to Determine Front Line Therapy in Metastatic Non-Small Cell Lung Cancer (NSCLC)

In the last decade, non-small-cell lung cancer (NSCLC) treatment has improved with the approval of multiple therapies to target specific genetic alterations. Though, next generation sequencing (NGS) has traditionally been conducted from tissue biopsy samples, developing data supports the use of plasma-based circulating tumor DNA (ctDNA), also known as "liquid biopsy," to complement tissue biopsy approaches in guiding front-line therapy. This study is a retrospective analysis of 170 new NSCLC patients treated at 2 cancer centers within a 5-year period who received both tissue and liquid biopsy NGS as standard of care. Based on a treatment schema defined by testing sufficiency, biomarker detection, and turnaround time (TAT), physicians based the majority of their treatments on liquid biopsy results (73.5%) versus tissue biopsy (25.9%). Liquid biopsy NGS returned results on average 26.8 days faster than tissue and reported higher testing success. For guideline-recommended biomarkers, liquid biopsy was 94.8% to 100% concordant with tissue. In comparing testing modalities, a liquid-first approach identified guideline-recommended biomarkers in 76.5% of patients versus 54.9% in a tissue-first approach. There was no significant difference in time-to-treatment, or survival outcomes (overall survival and progression free survival) based on liquid versus tissue biopsy findings. This research demonstrates that liquid biopsy NGS is an effective tool to capture actionable genetic alterations in NSCLC. Due to its high concordance to tissue, faster TAT, and similarity in outcomes and time-to-treatment, liquid biopsy can be used either as a first-line test or concordantly with tissue biopsy to guide treatment decisions in NSCLC.