Breast Cancer Screening

The average lifetime risk of breast cancer for women in the United States has been estimated to be 12.3% (one in eight women). In 2009, an estimated 194,280 cases of invasive breast cancer (192,370 women, and 1919 men) and 62,280 cases of carcinoma in situ (early localized breast cancer) of the breast will be diagnosed in the United States with 40,610 deaths from invasive breast cancer predicted. The good news is that death from breast cancer has dropped slightly. This decrease has been attributed, in part, to mammographic screening.

Despite controversies in the news media, good-quality recent scientific evidence indicates that screening mammography saves lives in women when performed annually and when started at age 40. This is a new recommendation. Previously, it was unclear whether mammography should be performed in women between 40 and 50 years of age, and if performed how often it should be done. It is unclear if there is any age at which it should be stopped, although most experts recommend that if a woman appears to have a life expectancy under 10 years, continued mammography may not be necessary.

Experts also indicate that mammography, and other imaging modalities, should not be used alone, and results should be interpreted within the context of patient history, including personal and family history and symptoms, physical examination, and careful clinical judgment by a health care provider.

The exact components of a breast screening evaluation are dependent on patient age and other factors such as medical and family history, and can include breast awareness (patient familiarity with her breasts and any changes as noted by the patient), physical examination, risk assessment, screening mammography, and, in selected cases, screening magnetic resonance imaging (MRI).

In average risk women ages 20-39, breast self-awareness is encouraged, and clinical breast examination is recommended every 1-3 years.

In average risk women ages 40 and above, breast self awareness is encouraged, and yearly mammography and clinical breast examination are recommended. It is unclear what should be done in women over 70. Most experts recommend that if a woman appears to have a life expectancy under 10 years, continued mammography may not be necessary.

Determining who is at higher than average risk can be achieved using computer-aided analysis of personal and family history but should be interpreted by a health professional. Things that can affect risk include personal or family history of breast or ovarian cancer, history of breast biopsies, menstrual history, pregnancy history, and breast feeding history.

MRI of the breast is generally more sensitive than mammography, but it is more likely to indicate an abnormality when there is nothing wrong, leading to a higher number of unnecessary biopsies. In addition, it does not pick up microcalcifications, which are tiny areas of calcium in the breast, which are the only detectable feature of some breast cancers. Screening MRI of the breast is currently only recommended for certain specific groups of women at high risk.

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