Ca 15.3 (Breast Cancer)

The CA 15.3 (Breast Cancer) test is primarily used as a biomarker to monitor the treatment progress and recurrence of breast cancer. It is exceptionally helpful because it tracks the levels of a protein that is often shed into the bloodstream by tumor cells, since rising levels can alert clinicians to cancer progression or metastasis even before physical symptoms or imaging results become apparent. While it is not used for general screening due to potential elevations in benign conditions, for those already diagnosed, it provides a non-invasive barometer to evaluate if a specific therapy is working or if the disease has returned.