ctDNA positivity indicates which of the following?

• A. Lower recurrence risk
• B. Higher recurrence risk / worse prognosis
• C. No impact on prognosis
• D. Immediate treatment change

Answer: (B)

ctDNA positivity signals residual cancer activity in the body, meaning there are tumor cells still present after initial treatment. Those tumor DNA fragments in the blood reflect micrometastatic or minimal residual disease that imaging may miss. Because this indicates ongoing disease, the risk of relapse is higher and disease-free and overall survival tend to be worse for ctDNA-positive patients. This is why ctDNA positivity is considered a negative prognostic biomarker and is associated with a higher recurrence risk.

While ctDNA results can influence monitoring and treatment decisions, it does not automatically mandate an immediate treatment change; decisions depend on the cancer type, stage, patient factors, and overall clinical context.