Which biomarker is used to monitor treatment progress in ovarian cancer?

• A. CEA
• B. AFP
• C. CA-125
• D. CA 19-9

Answer: (C)

During treatment of ovarian cancer, a serum marker that tracks tumor burden over time is used to gauge how well therapy is working. The marker most commonly used for monitoring response is CA-125. When chemotherapy is effective, CA-125 levels usually fall, and a rising level can suggest progression or recurrence. Because trends across several measurements are more informative than a single value, clinicians look at how CA-125 changes with each cycle and alongside imaging studies and clinical findings.

CA-125 is not perfect, though. Some ovarian cancers don’t produce much CA-125, and it can be elevated in benign conditions such as endometriosis, liver disease, or inflammation, so results must be interpreted in the full clinical context and with imaging. Other biomarkers like CEA, AFP, and CA 19-9 are used for other cancer types and are not standard tools for monitoring ovarian cancer, which is why CA-125 is the best choice for tracking treatment progress in this setting.