What is the primary use of CA-125 measurement in ovarian cancer management?

• A. CA-125 is used for screening asymptomatic women.
• B. CA-125 has high sensitivity for early disease.
• C. CA-125 is not used for monitoring.
• D. CA-125 is used primarily for monitoring disease in patients with known ovarian cancer.

Answer: (D)

CA-125 is best used for monitoring disease in patients with known ovarian cancer because its level generally reflects the amount of tumor burden and how well treatment is working. Serial measurements show trends: a decreasing CA-125 during chemotherapy suggests a favorable response, while a stable or rising level can indicate persistent disease or relapse. After treatment, rising CA-125 can prompt further imaging to look for recurrence. It’s not reliable as a screening tool in asymptomatic women because benign conditions and non-ovarian factors can raise CA-125, and early ovarian cancer often does not produce a high value, leading to many false positives or false negatives. While CA-125 can contribute to prognosis and management in select contexts, its primary role in routine practice is monitoring those with known ovarian cancer.