Liquid Biopsy in Gastroenterology

Clinical Applications

The National Comprehensive Cancer Network (NCCN) guidelines recommend liquid biopsy using validated NGS-based comprehensive genomic profiling in CLIA-approved laboratories for patients with advanced or metastatic gastric cancer who cannot undergo traditional biopsy or for disease progression monitoring 1, 2
Liquid biopsy can detect biomarkers such as HER2/ERBB2 amplification, MSI status, MMR deficiency, TMB-H, and NTRK gene fusions when tissue is limited 1
ctDNA NGS analysis can identify targetable alterations in 69% of advanced gastroesophageal adenocarcinoma patients 2
Liquid biopsy can be used for real-time monitoring in patients unable to undergo repeat tissue biopsies 1
A negative liquid biopsy result must be interpreted with caution, as it does not exclude the presence of tumor mutations or amplifications 1, 2

The American College of Pathology recommends IHC, in situ hybridization (ISH), or targeted PCR for specific biomarkers as the first-line approach when tissue is limited or biopsy is not feasible 1
NGS-based assays performed in CLIA-approved laboratories can provide comprehensive genomic analysis 2
Only validated assays should be used for clinical decision-making 1, 2

The major limitation of liquid biopsy is that its sensitivity varies significantly by cancer stage, tumor burden, and biomarker type 5
Liquid biopsy is currently most appropriate for advanced disease settings, particularly when traditional biopsy is contraindicated or for longitudinal monitoring 1, 2
Liquid biopsy should not replace tissue biopsy when adequate tissue can be safely obtained, initial diagnosis and staging are required, or histologic subtype classification is needed for treatment planning 1

Emerging applications of liquid biopsy include cancer screening, minimal residual disease monitoring, therapy response prediction, and extracellular vesicle analysis 8