Understanding Circulating Tumor DNA (ctDNA)

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Circulating Tumor DNA (ctDNA) refers to fragments of DNA from cancer cells that are found in the bloodstream, providing valuable insights into the genetic makeup of tumors. In this video, we explain how ctDNA can help guide personalized cancer treatment and monitor disease progression.

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‍Read the full video transcript below:

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This video is an overview of circulating tumor DNA for patients. Circulating tumor DNA is a valuable tool in cancer detection and management. Here's what you need to know about circulating tumor DNA:

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Circulating tumor DNA, also known as ctDNA, originates from cancer cells and is found in the bloodstream. It consists of small fragments of DNA that are released into the blood when cancer cells die and break down.

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There are several key points to remember about ctDNA. CtDNA can be used to detect and diagnose tumors as it contains genetic changes specific to cancer cells. This method can sometimes reduce the need for invasive tumor biopsies. Sometimes, ctDNA can help doctors identify specific targeted drugs for patients who may not respond to more typical treatments like chemotherapy. Changes in ctDNA levels can indicate treatment effectiveness; a decrease in ctDNA might suggest the tumor is shrinking.

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CtDNA tests are highly sensitive and can detect minimal residual disease, also known as MRD, before it's visible on imaging scans like CTs and MRIs. Earlier detection allows doctors to step in with additional treatments earlier than they otherwise would if they had to wait for the tumor to show up on scans.

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CtDNA analysis is done through a blood test, making it a liquid biopsy that's less invasive than traditional tissue biopsies. While ctDNA testing is most advanced for colorectal cancer, it's also used in breast, non-small cell lung cancer, and muscle-invasive bladder cancers. CtDNA levels generally correlate with tumor size and progression, increasing as the tumor grows and decreasing with successful treatment. In 2016, the first ctDNA liquid biopsy test was approved by the FDA for detecting EGFR mutations in non-small cell lung cancer patients.

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It's important to note that while ctDNA testing is promising, it's not yet widely used for all cancer types. The presence of ctDNA indicates a high risk of recurrence but doesn't necessarily mean immediate treatment is needed. As research continues, ctDNA analysis may play an increasingly important role in personalized cancer care and monitoring.

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This is not medical advice. Talk to your doctor before making any medical decisions.

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