Liquid Biopsy for Lung Cancer: How It Works

Liquid biopsy is a blood test that detects circulating tumor DNA (ctDNA) — small fragments of genetic material shed by tumor cells — as a less invasive alternative or complement to traditional tissue biopsy.

Traditional biopsies require obtaining a physical tissue sample, which can be invasive and, in some cases, difficult to repeat over time to monitor how a cancer is changing. Liquid biopsy testing instead analyzes a routine blood draw for ctDNA, potentially identifying targetable mutations or monitoring treatment response without repeated invasive procedures.

Researchers are studying liquid biopsy for several potential uses: identifying actionable mutations at diagnosis when tissue is limited or unavailable, monitoring for emerging resistance mutations during treatment, and detecting molecular signs of recurrence earlier than imaging might show it.

Liquid biopsy technology continues to be refined, and its sensitivity — how reliably it can detect ctDNA when present — remains an active area of ongoing research and technology development.