Mammograms, demystified

What is a mammogram?

A mammogram is a low-dose X-ray procedure that enables doctors to see the internal structure of the breast and possibly detect breast cancers that cannot be felt. These smaller tumors are more likely to be confined to the breast, meaning treatment is more likely to be successful.

While mammography is not perfect, getting a high-quality mammogram is currently the most effective way to detect breast cancer early. Mammography can identify breast cancer before physical symptoms develop, when the disease is most treatable.

Death rates for breast cancer have steadily decreased in women since 1989, with larger decreases in younger women; from 2005 to 2009, rates decreased 3.0 percentage per year in women younger than 50 and 2.0 percent per year in women 50 and older. The decrease in breast cancer death rates represents progress in earlier detection, improved treatment, and possibly decreased incidence as a result of declining use of menopausal hormone therapy.

When should women have mammograms?

The American Cancer Society’s current breast cancer screening guidelines are as follows:

Yearly mammograms are recommended starting at age 40 and continuing for as long as a woman is in good health. Women with serious health problems or short life expectancy should discuss ongoing early detection testing with their health care providers.

A breast exam should be part of a periodic health exam, at least every three years for women in their 20s and 30s and every year for women age 40 and older.

Women should know how their breasts normally look and feel and report any breast change promptly to their health care providers. Breast self-exam is an option for women starting in their 20s, and women should be told about the benefits and limitations of breast self-exam.

The American Cancer Society recommends that some women ­­— because of their family history, a genetic tendency, or certain other factors — be screened with magnetic resonance imaging (MRI) in addition to mammograms, starting at age 30. (The number of women who fall into this category is less than 2 percent of all the women in the United States.) Women who think they are in this category should talk with their doctor about their history and whether they should have an MRI with their mammogram.

Does mammography detect all breast cancers?

While mammograms detect the majority of breast cancers, they are not perfect and fail to detect about 10 to 20 percent of breast cancers. Women with negative mammograms who find a change in their breast should be certain that their breast change is evaluated by their doctor.

Is mammography the only technology currently used to screen for breast cancer?

Mammography is the standard tool for early detection today. Other imaging techniques, however, are under investigation. These include MRI, positron emission tomography (PET), and ultrasound. Some of the techniques are currently used to follow up on suspicious findings from a physical exam or mammogram or along with mammography in women with increased risk for breast cancer.

­The American Cancer Society