CA 15.3 Test (Cancer antigen 15.3)

CA 15.3 test is named from the words “cancer antigen” or “carbohydrate antigen”. CA 15.3 test is used to monitor the breast cancer treatment and to determine the recurrence  of breast cancer.

What is CA 15.3 ?

CA 15.3 is a protein that is produced by normal breast cells, its level increases in most of the breast cancer cases. CA 15.3 level may be increased in 10-20% of  early stage (stage I-II) breast cancer patients but its level increases in 70-80% of patients with metastatic and recurrent breast cancer. CA 15.3 level increases in 75% of patients who have progressive cancer, and decreases in patients who are responding to therapy.

How the CA 15.3 Test is done?cea 15.3

CA 15.3 Test is done in serum so you’ll need to give a tube of blood for CA 15.3 Test. Blood collection is an easy and short procedure for you. All process takes 1-2 minutes at most and you may feel a little pain for a few seconds during the blood collection.

Factors that need attention

Tumor markers are not evaluated by standart methods, different laboratories use different analysis methods so comparison of different laboratories may cause wrong evaluation of test results. If you need to have CA 15.3 Test periodically, please have the test in the same laboratory everytime.

High CA 15.3 causes

CA 15.3 Test result may be increased in breast cancer and also lung, pancreas, colon, prostate and ovary cancers. At the same time cirrhosis and hepatitis may cause increasing in CA 15.3 Test.

What does high CA 15.3 Test result mean?

Breast cancer is the first reason of a high CA 15.3 Test result and its level may be increased in the situations as listed above. In breast cancer treatment if the CA 15.3 level is found high or continues increasing, this means the treatment is not successful or the breast cancer is relapsed. For a correct evaluation , the breast cancer type should be a cancer type that produces so much CA 15.3. If it is a type that doesn’t produce high levels of CA 15.3 , the test can’t be used as a tumor marker.

A high CA 15.3 level in breast cancer patients means that cancer has spread to bones and lungs. CA 15.3 result should not be used to detect cancer presence by itself; test result must be evaluated with patient’s clinical examination and other diagnosis tools.


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