Breast Cancer Risk Factor
How Will I Know?
Does This Risk
Age
The chance of getting breast cancer increases as you
get older. If you are over age 60, you are at greatest risk.
If you have not yet gone through menopause, your risk of
breast cancer is lower than for women who have gone through menopause.
Personal history of breast cancer
If you have had breast cancer in one breast, you have an
increased risk of getting it in the other breast.
Family history of breast cancer
If your mother, sister, or daughter has had breast cancer
(especially before age 40), your risk is higher. Having other
relatives with breast cancer (on either your mother’s
side or your father’s side) may increase your risk.
Certain breast changes
Breast changes occur in almost all women. You might notice
different kinds of breast changes at different times of your
life. Most of these changes are not cancer. However, some
changes may be signs of cancer.
Genetic alterations
Approximately 5 to 10 percent of American women who get
breast cancer each year have a hereditary form of the disease.
You are at increased risk for this form of the disease:
If your family has a history of multiple cases of breast
cancer
If your family has a history of cases of both breast
and ovarian cancer
If you have one or more family members with two primary cancers at different sites
If you are of Ashkenazi (Eastern European) Jewish background.
See Genetics and breast cancer in the blue
area above to find out more.
Menstrual history
If you began to menstruate early (before age 12), you are
at increased risk. If you went through menopause late (after
age 55), you are at increased risk.
Radiation therapy to the chest
If you had radiation therapy to the chest (including your
breasts) before age 30, you may be at increased risk. The
younger you were when you received the radiation treatment,
the higher your risk of breast cancer later in life.
Breast density
If you are an older woman who has dense (not fatty) tissue
on a mammogram, you are at increased risk.
Research has shown that women age 45 or older who have at least 75
percent dense tissue
on a mammogram are at increased risk of developing breast cancer. Scientists
do not completely understand the reasons for this.
DES (diethylstilbestrol)
DES is a synthetic form of estrogen that was given to some
pregnant women in the United States between about 1940 and
1971. It is no longer given to pregnant women. If you
took DES during pregnancy, you have a slightly increased
risk of breast cancer. This does not appear to be the case
for the daughters exposed to DES when their mothers were
pregnant. However, as those daughters grow older, more studies
of breast cancer risk are needed.
Reproductive history
The older you were when you had your first child, the greater
your risk of developing breast cancer. If you have never
had children, you also are at increased risk.
Hormone use (such as estrogen and progestin)
If you have
used menopausal hormones
(also called
hormone replacement therapy or HRT)—either estrogen
alone or estrogen plus progestin—for 5 or more years
after menopause, you may have an increased risk of developing
breast cancer.
Here are the basic facts about menopausal hormone use.
They are based on the results of a large clinical trial,
called the Women’s Health Initiative:
Estrogen plus
progestin
(combined therapy)
increases the risk of breast cancer (as well
as heart disease, stroke, and blood clots).
Women over age
65 who took the combined therapy doubled their risk of
developing dementia.
There were fewer cases of hip fractures
and colon cancer among women who used the combined therapy.
See Menopausal hormone use in the blue
area above to find out more.
Obesity after menopause
If you are obese after menopause, you have 1.5 times the
risk of developing breast cancer
compared to women of a healthy weight.
This risk seems to apply only to postmenopausal women who
do not use menopausal hormones. Among women who use these
hormones, there is no significant difference in breast cancer
risk between obese women and women of a healthy weight.
Physical inactivity
There is a strong correlation between lack
of physical activity and obesity. A recent study from the Women’s
Health Initiative found that physical activity among postmenopausal
women who walked about 30 minutes per day was associated with
a 20 percent reduction of breast cancer risk. However, this
reduction in risk was greatest among women who were of normal
weight. For these women, physical activity was associated with
a 37 percent decrease in risk. The protective effect of physical
activity was not found among overweight or obese women.
Alcoholic beverages
Having two or more drinks each day increases
your risk of getting breast cancer by about 25 percent. (A
drink is defined as 12 ounces of regular beer, 5 ounces of
wine, or 1.5 ounces of 80-proof liquor.)
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