Risk factors
What is breast cancer?
Other than skin cancer, breast cancer is the most common form of cancer in women in the United States. More than 200,000 women are diagnosed with breast cancer each year. Incidence
rates have increased every year since the 1980s, especially in women 50 years of age and older, although the rate of increase slowed starting in the 1990s. Much of this increase
has been credited to changes in reproductive patterns, such as delayed childbearing and having fewer children, and to improved methods of detection. Improved methods of detection
and increased awareness, however, have also increased the chances for successful treatment and survival.
Certain factors have been shown to put people at greater risk for developing breast cancer. Make sure your physician is aware of any risk factors you may have, such as:
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Advanced age (greater than 65) |
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Late menopause (greater than or equal to 55 years of age) |
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Family history of breast cancer, especially if you have one or more first-degree relatives (mother, sister, or daughter) diagnosed at an early age |
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Alcohol consumption (greater than or equal to 2 drinks per day) |
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First child at or after age 30 or no full-term pregnancies |
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Recent use of estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) |
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Early first period or menarche (less than 12 years of age) |
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Obesity after menopause |
Recent research has shown that previous use of HRT—a combination of estrogen and progestin—is associated with an
increased risk of invasive breast cancer. However, this increased risk was generally small and did not appear until after 4 years of HRT use.
Inside the breast are small sacs, or glands, that start producing milk late in pregnancy. The glands empty into small channels, or ducts, that carry the milk toward the
nipple. For reasons that are still unknown, the cells lining the glands and ducts sometimes begin to grow and divide abnormally. This abnormal cell growth can form a mass or
tumor and may lead to breast cancer.
