Why would I need this test?
A mammogram is an x-ray of the breast. Mammography is used for early detection or diagnosis of breast cancer.
A screening mammogram is one that is done to find breast cancer before it causes symptoms. A screening mammogram usually involves two pictures of each breast (one from the top, one from the side).
Screening mammograms can find breast cancer up to two years before a lump can be felt. Treatment is most successful when breast cancer is found early.
A diagnostic mammogram involves more x-rays taken from different angles to get detailed pictures of the breast tissue. A diagnostic mammogram may be needed if a woman or her doctor notices any signs that could point to breast cancer. These include:
- A lump or thickening in the breast or armpit
- A change in the size or shape of the breast
- Puckering or dimpling of the skin on the breast
- A nipple turned inward into the breast
- Fluid (discharge) from the nipple, especially if it's bloody
- Scaly, red, or swollen skin on the breast, or ridged or pitted skin that looks like the skin of an orange
At what age should I start getting mammograms?
Experts disagree about the best age for women at average risk of breast cancer to start getting mammograms:
- The American Cancer Society recommends that women have a mammogram and clinical breast exam every year starting at age 40.
- The U.S. Preventive Services Task Force (USPSTF) suggests that women start having mammograms at age 50 and repeat them every two years. This group also encourages women younger than 50 to talk to their doctor so they can make an informed decision about screening.
These are general recommendations that do not take into account your personal or family medical history. Some women may need to start screening at an earlier age.
Bottom line: Talk to your doctor about your risk for breast cancer and your personal feelings about screening for this disease. Your doctor can suggest a screening schedule that is right for you.
Are there different types of mammography?
Digital mammography (DM) is a new type of breast cancer screening. It is done the same way as a regular mammogram. But instead of storing the images on film, a digital mammogram records and stores the images on a computer. Digital mammography may be better than film mammography at finding cancer in women younger than 50 and women with dense breast tissue.
Digital mammography is not yet available at all testing centers.
How do I prepare for this test?
The best time to schedule a mammogram is about a week after your menstrual period. Find out if you should bring films from your previous mammograms or a copy of your complete health history.
On the day of your mammogram:
- Do not use deodorant, talcum powder or lotion on your breasts or underarms. They could interfere with the test.
- Wear a two-piece outfit so you can remove only the top half of your clothing.
It's also important to:
- Tell the doctor or testing center if there is any chance that you might be pregnant.
- Let the technician know if you have breast implants. He or she may need to use a different procedure or take more views of your breasts.
How is this test done?
During a mammogram, you will rest one uncovered breast between two flat plastic plates on the mammography machine. The plates are then pressed together. Spreading the tissue out makes any abnormal details easier to spot with the least amount of radiation. You will be asked to hold your breath and stay still while the technician takes the x-ray.
The procedure is then repeated for the next view. A screening mammogram usually consists of four x-rays - a top view and a side view of each breast.
The pressure from the plates can be uncomfortable or even somewhat painful for some women. You should talk to your technician if you are concerned about discomfort or if you have pain during the procedure. If you have discomfort, it helps to remember that each x-ray takes less than one minute and could help save your life.
How long does the test take?
An entire mammogram screening takes about five to 10 minutes, and you are exposed to radiation for only a few seconds. However, you may be asked to wait while the images are checked to make sure they are clear. In some cases, more x-rays may be needed.
Before you leave, find out when your results will be ready. Don't assume that "no news is good news." If you don't get your results when expected, be sure to call and ask for them.
Are there any risks associated with this test?
The main risks are:
- Radiation exposure. However, the amount of radiation a woman is exposed to during a standard mammogram is very low, about the same as from getting dental x-rays.
- False-positive results. About one in 10 mammograms is a false-positive, meaning it shows a problem when there isn't one. This can lead to unnecessary fear and the expense of follow-up testing.
What is a desirable result?
A normal mammogram will show healthy breast ducts, glandular tissue and fat. No abnormal lumps or masses should be seen.
What happens if my mammogram is abnormal?
A screening mammogram looks for suspicious areas of breast tissue. If your mammogram is abnormal or unclear, you may be asked to return for a diagnostic mammogram, which involves more views and more detailed pictures.
You may also be referred for additional testing such as:
- Ultrasound of the breast. This test uses sound waves to help distinguish between breast masses that are solid and those that are fluid-filled.
- Needle aspiration. For this test, a needle is inserted into a lump to find out if it is fluid-filled or solid. A sample of fluid or tissue may be taken and sent to a lab.
- Biopsy. In this procedure, a small incision is made in the breast to remove an entire growth or a sample for study under a microscope.
It's important to understand that an abnormal screening mammogram result does not necessarily mean that you have cancer. Many things can cause an abnormal result. It simply means you need follow-up testing.
Created on 08/01/2001
Updated on 08/27/2010
- U.S. Preventive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine. 2009;151(10):716-726.
- American College of Radiology. Mammography.
- National Cancer Institute. Mammograms.
- American Cancer Society. Mammograms and other breast imaging procedures.
- National Cancer Institute. What you need to know about breast cancer.