Identifying women at high risk for breast cancer

Early menarche and late menopause lead to an increased total lifetime number of menstrual cycles. If women who experience menopause between the ages of 45 and 55 are used as the reference group, then a 50% higher relative risk of subsequently developing breast cancer is present in women who experience menopause at 55 or older. A 30% lower relative risk of breast cancer is present in women who cease menstruating at age 45 or younger.

Common questions about your risk for breast cancer

Breast cancer is the second leading type of cancer in women, with roughly 175,000 new cases of invasive cancer diagnosed annually in the United States, and 44,000 women who die of the disease. Do not take to heart what you hear about an American woman's "1 in 8" lifetime chance of developing breast cancer; it tells you little about your own personal risk. Whether you're overestimating or underestimating your risk of developing breast cancer, keeping up important self-examinations and regularly scheduled screening mammographies remains the best advice for everybody.

Although most women greatly overestimate their risk of breast cancer and overlook their far greater likelihood of dying from heart disease, others do underestimate their personal, individual risk. How do you know where you stand? To give you - not a perfect - but a ballpark idea, the National Cancer Institute (NCI) is now offering its Breast Cancer Risk Assessment tool, an easy-to-use and free 3¹/₂-inch floppy "risk disk" to help you and your obstetrician-gynecologist try to sort out your risk (see "The risk disk: putting the numbers into perspective" for a sample calculation of how the program works). If your risk appears to be high, you may benefit from taking a drug that appears to prevent breast cancer.

Other risk factors for breast cancer (in descending order) include:

• Age older than 60 years

• Living in a developed country

• Previously having atypical breast hyperplasia

• Previously diagnosed lobular carcinoma in situ of the breast

• Having cancer in the contralateral breast

• Beginning menarche before age 11

• Having first child in early 40s

• Being exposed to abnormal levels of ionizing radiation as a young female after age 10

• First-degree relative whose breast cancer was diagnosed before age 40

• Using diethylstilbestrol during pregnancy

• Having postmenopausal body mass index greater than 35

• High intake of saturated fat

• Using HRT for 10 years or more

• Consuming too much alcohol