“CA” stands for “Cancer Antigen.” That means the CA 15-3 blood test is ordered to determine the presence of a specific antigen that is present in the body when cancer may be there. In this instance, it is commonly ordered as part of a blood test panel to determine the presence of breast cancer. Most medical providers will not order this blood test as part of a screening process, however, as it is generally accepted that it is not sensitive enough to do so.
The CA 15-3 blood test is most commonly ordered to monitor how well someone is responding to their cancer treatment plan. Some medical providers may also use this specific blood test to help determine how much of a cancer or tumor burden a patient may be facing.
Not all breast cancer types will create the CA 15-3 marker, so the CA 15-3 blood test is not appropriate for all patients, including those who may have already been diagnosed with cancer.
When To Ask About the CA 15-3 Blood Test
The CA 15-3 blood test is often ordered with a panel of other tests if there is a strong suspicion of advanced cancer in a patient. These additional tests may include estrogen and progesterone receptor testing and gene expression tests. This can help a medical provider to determine what the characteristics of the cancer might be.
For patients that have already been diagnosed with breast cancer, the CA 15-3 test is used to track the treatment progress being made. If breast cancer is suspected to be in its earliest stages, however, the CA 15-3 test may not be ordered because most cancers will not shed this antigen when they first develop.
What Do My CA 15-3 Blood Test Results Mean?
People who are healthy may have mild to moderately high levels of CA 15-3 in their blood and not have cancer. Even though it is called a “cancer antigen,” there are certain benign conditions that can cause this antigen to appear. This can include hepatitis, certain ovary disorders, and benign tumors in breast tissues. When it appears with a non-malignant condition, then concentrations tend to be stable over time.
When ordered because of suspected breast cancer, the general rule of thumb for this test is that higher concentration levels of CA 15-3 indicate higher cancer concentration levels. It can also be an indication of the tumor burden a patient may be facing. The highest levels of CA 15-3 are typically seen in patients who have had their breast cancer metastasize into their liver or into their bones in the latest stages of a cancer diagnosis.
If the CA 15-3 blood test has been ordered to monitor ongoing treatment of breast cancer, then increasing concentrations of this antigen are a general indication that a patient is not responding to their treatment plan.
Here’s What You Need To Know
CA 15-3 blood test results can be rather transient in nature. This means they can be somewhat high on one test and then somewhat low on another test. This tends to occur right after a breast cancer diagnosis has taken place. For this reason, a medical provider may be hesitant to order this test because the results received may not be reflective of a patient’s current condition. Most CA 15-3 blood tests will be ordered several weeks after the initial diagnosis takes place.
Even if you have a strong family history of breast cancer, the CA 15-3 blood test is still not a suitable test for screening purposes. Not only are their sensitivity issues that must be considered, but this antigen could be present for non-cancerous reasons as well. A full medical workup is generally necessary for a diagnosis when CA 15-3 is found to be present.
There is nothing that a patient can do to naturally lower their risks of having a positive or high CA 15-3 blood test. This is because the test is used to determine the status of a disease that is present in the body. Even people who have low risks of cancer development can still be diagnosed with breast cancer and wind up having a positive test.
Early treatment helps people be able to beat cancer much more often. Being proactive about your health is the best approach to take. Most people who receive the CA 15-3 blood test have already been diagnosed with breast cancer or some other cancer and have been being treated for it. If you have any questions about this test or whether it should be ordered for you, then speak with your medical provider about the benefits of what having these test results could mean for your personal health.