CA125, or cancer antigen 125, is a protein found in the blood. A CA 125 test measures the amount of this protein. While elevated levels are often associated with ovarian cancer, it's important to understand that CA 125 is not a definitive diagnostic tool for ovarian cancer alone.
Uses of the CA 125 Test
The CA 125 test has several applications in medical care:
- Monitoring Ovarian Cancer: The test is primarily used to monitor the response of ovarian cancer to treatment and to detect recurrence after treatment. [Mayo Clinic, MedlinePlus, Cleveland Clinic, Canadian Cancer Society]
- Assessing Other Cancers: Although most commonly associated with ovarian cancer, elevated CA 125 levels can sometimes be seen in other cancers, like endometrial, breast, and pancreatic cancers. [Canadian Cancer Society, Stanford Health Care]
- Early Detection (High-Risk Individuals): In women with a significantly increased risk of ovarian cancer, the test might be used as part of a screening strategy to detect early signs of the disease. [Mayo Clinic]
Important Considerations:
- Not a Diagnostic Test: A high CA 125 level doesn't automatically mean ovarian cancer. Many non-cancerous conditions can also cause elevated levels. [Cleveland Clinic, Target Ovarian Cancer]
- Normal Range Varies: The normal range of CA 125 can vary between labs. Results should always be interpreted by a healthcare professional in the context of a patient's overall health and other diagnostic tests. [Medscape]
- Limitations: CA 125 is not always elevated in early-stage ovarian cancer, and some women with ovarian cancer may have normal CA 125 levels. It is more helpful in monitoring disease progression than in initial diagnosis. [OCRA, Target Ovarian Cancer]
CA125 in Research
Ongoing research continues to explore the role of CA125 in cancer diagnosis, treatment, and prognosis. Its importance as a biomarker for ovarian cancer is well established, but research is ongoing to improve its clinical utility and understand its use in other conditions. [NCBI PMC]
