circulating tumor DNA
Also written as: ctDNA — circulating tumor DNA
Fragmented DNA released by cancer cells into the bloodstream, detectable through liquid biopsy techniques.
Full Definition
Circulating tumor DNA (ctDNA) refers to short fragments of DNA shed by cancer cells into the peripheral circulation, representing a subset of cell-free DNA. These fragments carry tumor-specific genetic alterations including mutations, copy number variations, and methylation patterns. Detection and analysis of ctDNA through liquid biopsy techniques enables non-invasive monitoring of tumor burden, treatment response, and resistance mechanisms. Clinical applications include early detection of recurrence, real-time monitoring of treatment efficacy, and identification of actionable mutations when tissue biopsy is not feasible.
Usage
Usage note: Use lowercase 'c' when writing out 'circulating' but uppercase when abbreviated as ctDNA.
In Context
- "Serial monitoring of circulating tumor DNA levels demonstrated a 90% reduction following two cycles of chemotherapy." — Treatment response assessment
- "The detection of EGFR T790M mutation in circulating tumor DNA prompted a switch to osimertinib therapy." — Molecular testing report