Which biomarker is most useful primarily for monitoring ovarian cancer treatment response rather than initial screening?

• A. CA-125
• B. ALT
• C. LDH
• D. MCV

Answer: (A)

In ovarian cancer management, a biomarker that mirrors tumor burden over time is most useful for monitoring how well treatment is working and for detecting recurrence, rather than for screening healthy people. CA-125 fits this role because its levels tend to rise as tumor mass increases and fall when effective therapy reduces that mass. Tracking CA-125 during chemotherapy helps determine whether the response is favorable and guides decisions about continuing, changing, or stopping treatment. After therapy, rising CA-125 can raise concern for relapse and prompt further imaging or evaluation.

However, CA-125 is not ideal for initial screening. Benign conditions such as endometriosis, menstruation, and pregnancy can elevate CA-125, and a significant number of early-stage ovarian cancers may not raise CA-125 at all, leading to false positives and false negatives. That’s why it’s used primarily for monitoring in patients with known ovarian cancer or those under surveillance after treatment, rather than as a population screening test.

The other options don’t serve this monitoring purpose. ALT is a liver enzyme used to assess liver injury. LDH is a nonspecific marker that can be elevated in many conditions, including various cancers, but it isn’t specific for ovarian cancer monitoring. MCV measures red blood cell size and is used in evaluating anemia, not cancer activity.