Join the Fight Against Breast Cancer!
Breast cancer is the most frequently diagnosed cancer in U.S. women, excluding cancers of the skin. If the current rate stays the same, women born today have about a 1 in 8 chance of developing breast cancer at some point during their lives. Although mortality rates have steadily decreased over the past decades, breast cancer remains the second leading cause of cancer deaths in U.S. women, exceeded only by lung cancer.
- Gender: Female gender is the most important risk factor for breast cancer. Men can develop breast cancer, but the risk for females is about 100 times greater.
- Age: As women age, the risk of developing breast cancer increases. About 66% of all invasive breast cancers are diagnosed in women age 55 and older, while about 12% are diagnosed in women younger than age 45.
- Race and ethnicity: In the U.S., Caucasian women are slightly more likely to develop breast cancer than are African-American women, although African Americans are more likely to die from this disease. Asian, Hispanic, and Native-American women have a lower risk than either Caucasian or African American women of developing and dying from breast cancer.2
- Family history of breast cancer: Risk is increased for women whose close relatives have breast cancer. In general, the more biological relatives with breast cancer, especially relatives diagnosed before age 50, the higher a woman's risk. Less than 15% of women with breast cancer have a positive family history in a first degree relative.
- Personal history of breast cancer: A history of breast cancer in one breast increases the risk of developing a new cancer in the other breast or in another part of the same breast by 3 to 4 times.
- Reproductive history: Certain reproductive factors slightly increase risk. These include giving birth to a first child after age 30, nulliparity (never having children), starting menstruation before age 12, and/or entering menopause after age 55. The increase in risk is likely due to a longer lifetime exposure to estrogen.
- Weight: Excess weight (as measured by body mass index) and/or weight gain after menopause is associated with a higher risk of breast cancer. In contrast, excess weight in premenopausal women has been associated with a lower risk. The reason for this observed relationship in premenopausal women is unclear.
- Alcohol: Compared with non-drinkers, women who drink alcoholic beverages are at increased risk. The risk increases with the amount of alcohol consumed. Risk for those who consume 2 to 5 drinks daily is increased by about 1½ times normal.
For women at average risk, the emphasis is on regular screening and healthy lifestyle choices (e.g., low-fat diet, regular exercise, breastfeeding). Women at increased risk for breast cancer are advised to consider additional risk reduction strategies in consultation with their health care providers.
- Physical activity: Regular physical exercise has been shown to provide some protection against breast cancer, especially in postmenopausal women. The reduction in risk for physically active women compared with women who are least active may be as much as 25%.
- Diet: A diet that is rich in vegetables, fruit, poultry, fish, and low-fat dairy products has been associated with a lower risk of breast cancer in some studies.2 There is also some evidence that soy-rich diets may reduce risk. Overall, however, the influence of dietary factors on breast cancer risk remains inconclusive.
- Breastfeeding: The risk reducing effect of breastfeeding has been shown in multiple studies, especially if the breast-feeding lasts 1½ to 2 years.2 For every year of breastfeeding, the reduction in relative risk has been estimated at approximately 4%.
National Cancer Institute (NCI). Breast cancer risk in American women. Accessed Jul. 30, 2013, from
American Cancer Society (ACS). Breast cancer: detailed guide. Accessed Jul. 30, 2013, from