1. Should I have a test for CA 27.29 in addition to the CA 15-3 test?
CA 27.29 is protein that is produced by the same gene (MUC1) as CA 15-3 and is used in the same way. It is newer than CA 15-3, but most doctors consider it essentially equivalent to CA 15-3. It can be used instead of CA 15-3, but you usually wouldn’t have both tests.
2. I have a strong family history of breast cancer. Shouldn’t I be screened for CA 15-3?
CA 15-3 is not recommended as a screening tool. It is not specific or sensitive enough to detect early breast cancer. Any CA 15-3 elevations seen may be due to other causes, and negative results do not ensure that you do not have cancer. It should only be used after breast cancer has been diagnosed.
3. What can I do to lower my CA 15-3?
There is nothing you can do directly to lower your CA 15-3 level. It is not a risk factor like cholesterol that can be lowered through dietary restrictions and exercise. It is a reflection of what is going on in your body. CA 15-3 may rise with tumor growth and fall with treatment, or it may be mildly elevated and stable in a benign condition.
