View Providers
A mammogram is a diagnostic image doctors use to look for abnormal breast tissue. It’s a powerful screening tool for breast cancer. A mammogram that spots something unusual in the breast can cause anxiety and worry. Many times, those abnormalities are not cancer. The results are a so-called false-positive. They may appear to be positive (cancer) at first. Further testing proves that the problem isn't cancer.
This happens to a lot of women. Up to half of all women who get a yearly mammogram starting at age 40 will get a false-positive result by age 50.
Who Gets a False-Positive Result
Some women are more likely than others to get a false-positive result after a mammogram. They include:
- Younger women
- Women with dense breasts
- Women who have had previous breast biopsies
- Women with a family history of breast cancer
- Women taking estrogen, which increases breast density
The odds of a false-positive result are highest the first time you have a mammogram. The odds go down with later mammograms. This explains why younger women have a greater chance of having a false-positive. This is largely because the doctor is not familiar looking at your breast tissue. It helps if the doctor who reviews the mammogram has copies of your previous mammograms for comparison. This can decrease your chances of having a false-positive result by 50%.
Other reasons for a false-positive include situations that make it difficult to tell normal from abnormal tissue, such as dense breasts.
What Comes Next After a False-Positive Result
All abnormal mammograms require more testing. Doctors need additional information to rule out or confirm breast cancer.
Additional testing may include:
-
Ultrasound: an ultrasound is painless imaging test to get a moving, real-time picture of the inside of the breast. It uses sound waves instead of X-rays.
-
MRI (magnetic resonance imaging): an MRI is another painless imaging test to get a detailed view of the inside of the breast. An MRI is useful for women with dense breasts, or other conditions in which it is hard to compare normal and abnormal breast tissue by mammography or ultrasound. A breast MRI is also important for women with a high risk of breast cancer and for women with a new diagnosis of breast cancer.
-
Biopsy: a small sample of breast tissue for testing by a pathologist. The pathologist looks at the tissue with a microscope for signs of cancer.
It’s normal to be anxious when you are notified about a positive mammogram result. You have to undergo more testing. Then you have to wait for results to say whether you do or do not have cancer. Then you feel a wave of new emotions when you learn that you do not have breast cancer because the screen mammogram registered a "false positive."
Perhaps surprisingly, researchers found a possible benefit to the false-positive experience. Women with a false-positive result were more likely to say that they would continue with future breast cancer screening than other women. Screening is the best way to find cancer early, if it does develop.
Mammography Tips
A mammogram is still one of the best tools for detecting breast cancer at an early stage. A yearly clinical breast exam and performing a breast self-exam on a regular basis are crucial. You need to know how your breasts look and feel at varying times, not just once a month. This will help you know when something isn’t right.
There are several practical things you can do to increase the accuracy of your mammogram. Here are a few:
-
Go to the same radiology facility each time you have a mammogram. This will ensure consistency between mammograms. Ask about the radiologist’s experience in interpreting breast X-rays. You may want to ask about the yearly rate of false-positives. This will give you a sense of accuracy in reading breast X-rays. The facility should be aiming for a false-positive rate below 10%.
-
Bring your previous mammograms with you, especially if you switch facilities. You can request a copy of the X-ray films be sent from one facility to another.
-
Ask another radiologist, preferably one with vast experience reading mammograms, for a second opinion if you get a false-positive result.
-
Don’t put lotion, body spray, or any other type of product on your upper body, not even deodorant. These products can interfere with the accuracy of the X-ray.