A mammogram is an X-ray test of the breasts (mammary glands) used to screen for breast problems, such as a lump, and whether a lump is fluid-filled (a cyst) or a solid mass.

A mammogram is done to help screen for or detect breast cancer. Many small tumors can be seen on a mammogram before they can be felt by a woman or her health professional. Cancer is most easily treated and cured when it is discovered in an early stage. Mammograms do not prevent breast cancer or reduce a woman's risk of developing cancer. However, regular mammograms can reduce a woman's risk of dying from breast cancer by detecting a cancer when it is more easily treated.

Experts have different recommendations for how often you should have a mammogram.¹

• For women older than age 50, regular mammograms (every 1 to 2 years) are recommended.
• For women between the ages of 40 and 50, the benefits of mammogram are not as clear. Talk with your health professional to determine when to start and how often to have a mammogram. Some organizations recommend mammograms every 1 to 2 years while others recommend mammograms every year. Most organizations recommend that women have their first mammogram at age 40.
• Your health professional may recommend testing more often if you have risk factors for breast cancer. Any woman with a personal or family history of breast cancer is recommended to have yearly mammograms.

A mammogram that appears to detect a cancer, when in fact a cancer is not present (false-positive results), can occur at any age but is more likely to occur in younger women. About 5% to 10% of screening mammograms will require more testing. This may include another mammogram of specific breast tissue (compression view) or another test, such as an ultrasound or biopsy. Most of these tests will show no cancer is present.

Why It Is Done

A mammogram is done to:

• Screen for breast cancer in women without symptoms.
• Detect breast cancer in women with symptoms. Symptoms of breast cancer may include a lump or thickening in the breast, nipple discharge, or dimpling of the skin on one area of the breast.
• Locate an area of suspicious breast tissue to remove for examination under a microscope (biopsy) when an abnormality is found.