CA -15.3 Test

The CA 15-3 test is a specialized blood examination used to detect the CA 15-3 tumor-associated serum marker in the bloodstream. This tumor marker is strongly linked to breast cancer, particularly non-metastatic and metastatic forms, and plays a crucial role in staging the disease, assessing therapeutic response, and monitoring the patient during and after treatment. When cancerous breast cells shed CA 15-3 into circulation, its levels can rise, making it a useful indicator for oncologists.

Because breast cancer risk increases with age, the CA 15-3 test is especially relevant for women over 40, with incidence peaking beyond age 50. Risk factors include a personal or family history of breast cancer, genetic mutations, breast tissue density, prior radiation exposure, hormonal changes, early onset of menstruation, late menopause, and long-term hormone therapy. All these factors contribute to prolonged estrogen exposure, which is closely associated with breast cancer development.

Although CA 15-3 is not typically used as a screening tool for healthy women, it is invaluable in ongoing cancer care—helping doctors determine whether treatment is effective, whether a suspected recurrence is taking place, or whether further investigation is required. By analyzing CA 15-3 trends along with clinical assessments and imaging studies, medical teams can make more informed decisions at every stage of patient management.

Measures CA 15-3 tumor marker levels in blood to help evaluate and monitor breast cancer activity.