What is CA 125?
CA 125, or cancer antigen 125, is a protein that is often found on the surface of ovarian cancer cells and is released into the bloodstream. It is commonly used as a
biomarker in gynecology to monitor the treatment and progression of ovarian cancer.
How is CA 125 Used in Gynecology?
CA 125 is primarily used to monitor the response to treatment in patients with ovarian cancer. It can also be used to detect a recurrence of the disease. Elevated levels of CA 125 may indicate the presence of ovarian cancer, but they can also be elevated in other
benign conditions such as endometriosis, menstruation, and pelvic inflammatory disease.
When is CA 125 Testing Recommended?
CA 125 testing is usually recommended for women who are at high risk for ovarian cancer or who have already been diagnosed with the disease. It is not typically used for routine screening in women who do not have symptoms or a high-risk profile. The test is often administered in conjunction with other diagnostic tools, such as
ultrasound and
CT scans.
Limitations of CA 125
While CA 125 is a useful marker, it is not infallible. Elevated CA 125 levels can occur in non-cancerous conditions, leading to false positives. Conversely, some ovarian cancers do not produce elevated CA 125, resulting in false negatives. Therefore, it should not be used as a standalone diagnostic tool but rather as part of a comprehensive diagnostic approach.Interpretation of CA 125 Results
CA 125 levels are typically measured in units per milliliter (U/mL). A level above 35 U/mL is generally considered elevated. However, the interpretation of results should be done by a healthcare provider who can consider other factors such as patient history, symptoms, and additional diagnostic tests.Role in Monitoring Treatment
In patients undergoing treatment for ovarian cancer, CA 125 levels are frequently monitored. A decreasing level of CA 125 generally indicates that the treatment is effective, while increasing levels may suggest that the cancer is not responding to treatment or is recurring. This helps in making decisions about continuing, changing, or stopping a particular treatment.Future Directions
Research is ongoing to improve the specificity and sensitivity of CA 125. Combining CA 125 with other biomarkers, like
HE4 (human epididymis protein 4), may enhance diagnostic accuracy. Additionally, advances in
genomics and
proteomics hold promise for identifying new biomarkers that could be used alongside CA 125 to provide a more comprehensive understanding of ovarian cancer.
