Case report: Liquid biopsy, the sooner the better?

Area of Science:

• Oncology
• Molecular Diagnostics
• Genetics

Background:

• Circulating tumor DNA (ctDNA) liquid biopsy is crucial for managing thoracic oncology, offering predictive and prognostic insights.
• It enables identification of targetable mutations, such as EGFR mutations in non-small cell lung cancer (NSCLC), for tyrosine kinase inhibitor (TKI) therapy.

Observation:

• A patient with severe hepatocellular failure and thrombotic microangiopathy, diagnosed with NSCLC, showed rapid clinical deterioration after salvage chemotherapy.
• Liquid biopsy identified an EGFR exon 19 deletion (EGFRDEL19) mutation with high ctDNA levels (736,400 copies/ml).

Findings:

• Despite a pre-mortem state, osimertinib treatment led to prompt and significant performance status improvement within one week.
• Tumor genotyping revealed EGFRDEL19, JAK3, and EGFR amplification, suggesting complex EGFR and JAK/STAT pathway interactions.
• Post-treatment imaging showed partial response, and ctDNA levels dramatically decreased to 40.0 copies/ml.

Implications:

• Liquid biopsy facilitated early targeted therapy, potentially saving the patient's life.
• Routine ctDNA testing at diagnosis, alongside tissue genotyping, is recommended for metastatic NSCLC patients with oncogenic addiction profiles.