What Is Circulating Tumor DNA (ctDNA)?
Circulating tumor DNA (ctDNA) refers to small fragments of a tumor's genetic material that can be detected in a routine blood draw, forming the basis of 'liquid biopsy' testing.
As tumor cells grow and die, they release small fragments of their DNA into the bloodstream. Highly sensitive sequencing technology can detect and analyze this ctDNA, potentially revealing the same mutations that a traditional tissue biopsy would show, without requiring an invasive tissue sample.
Beyond identifying targetable mutations, researchers are studying ctDNA as a way to monitor treatment response over time โ tracking whether ctDNA levels fall during effective treatment โ and as a potential early indicator of cancer recurrence after surgery, sometimes before it would be visible on imaging.
The sensitivity of ctDNA detection (how reliably it identifies tumor DNA when present, especially in early-stage or very small-volume disease) continues to be an active area of technology development and research validation.
Frequently Asked Questions
Is a ctDNA test the same as a regular blood test?
No โ it requires specialized sequencing technology specifically designed to detect small amounts of tumor-derived genetic material amid the much larger amount of normal DNA in blood.
Can ctDNA testing detect cancer before any other test?
Research into using ctDNA for very early detection or recurrence monitoring is ongoing and promising, but it is not yet a universal replacement for established diagnostic and monitoring methods.