A blood test for breast cancer usually involves taking a blood sample to learn more about a woman’s risk of developing breast cancer or to gain valuable information about its presence in a woman who has already been diagnosed with the disease. For example, one type of blood test for breast cancer is used to determine whether a woman has mutations of genes that may indicate an increased risk of developing breast cancer. Another type is used in evaluating how well breast cancer treatment is working. Still another type of test may be useful in assessing whether or not a case of breast cancer is getting worse or beginning to spread to other parts of the body.
One type of blood test for breast cancer is referred to as the BRCA gene test. This test is used to evaluate two genes, called BRCA1 and BRCA2, that indicate a person’s susceptibility to breast cancer. Mutations of these genes may mean that a woman is more likely to develop breast cancer. Mutations do not, however, mean that a woman has cancer or even that she will definitely develop it at some later date. If this test reveals that a woman is more susceptible to breast cancer than others, she may use this information to make decisions concerning the prevention of this type of cancer.
A cancer antigen test is another type of blood test for cancer. For example, cancer antigen 27.29 tests involve a protein called CA 27.29. When blood levels of this protein are rising, this typically means the patient’s cancer is getting worse; rising levels may even indicate that the cancer is spreading or has spread to other parts of the body. This test is not used to diagnose breast cancer but to help monitor the success of treatment and the status of the cancer. It may also be used to determine whether cancer has returned after breast cancer treatment.
CA 15-3 is also used as a blood test for breast cancer. As with CA 27.29, it is not used to diagnose breast cancer. Instead, it is used to detect a rise in levels of a protein called CA 15-3. It is typically used to evaluate the progression of cancer as well as the patient’s response to treatment. This particular blood test for breast cancer is usually used for advanced stages of cancer of the breast.
