Although the exact cause of
is not known, most experts agree that
there are several factors that increase your risk of breast cancer.
Top risk factors linked to breast cancer
- Aging.Your breast
cancer risk increases as you get older. By age group, breast cancer is
diagnosed in:5
- 4 out of 1,000 women in their
30s.
- 14 out of 1,000 women in their
40s.
- 26 out of 1,000 women in their 50s.
- 37 out of
1,000 women in their 60s.
- Being female. Although
breast cancer can occur in men, most breast cancer is found in women.
Conditions that increase the risk of developing breast cancer.
- Personal history of breast cancer. Women who have had breast cancer in one breast have an increased
chance of having another breast cancer. The breast cancer can come back in the
same breast, in the opposite breast, or in other areas of the body, such as the
lungs, liver, brain, or bones.
- Family history. A woman's risk of breast cancer increases if her mother,
sister, daughter, or two or more other close relatives, such as cousins, have a
history of breast cancer, especially if they were diagnosed with breast cancer
before age 50.
- Women who inherit specific changes ( mutations) in the
BRCA1 and BRCA2 genes are much more likely to have
breast cancer. They are also more likely to have
or
. But most women who have a family
history of breast cancer do not have changes in BRCA genes.
- Mutations in the BRCA1 and BRCA2 genes are more common
in certain ethnic groups, such as Ashkenazi Jews.
- Genetic tests are available to determine whether you
have the genetic mutations long before any cancer appears. In families where
many women have had breast or ovarian cancer, genetic testing can show whether
a woman has specific genetic changes known to greatly increase the risk of
breast cancer. Doctors may suggest ways to try to prevent or delay breast
cancer or to improve the detection of breast cancer in women who have the
genetic mutations. For more information, see
Breast cancer risk: Should I have a gene test for breast cancer?
- Breast changes. Women who have
,
, or
or who have had two
or more breast
for other noncancerous conditions are more
likely to have breast cancer.
Other factors that increase the risk of breast cancer
- Race. Breast cancer occurs more frequently in white women than in black, Hispanic, or
Asian women. But black women are more likely to get breast cancer at a younger
age and are also more likely to die of breast cancer.6
- Radiation therapy. Women whose breasts
were exposed to significant amounts of radiation at a young age, especially
those who were treated for
, have an increased risk for
developing breast cancer.
- Late or no childbearing. Women who had their first child after the age of 30 have a
greater chance of developing breast cancer than women who had their children at
a younger age. Women who never had children have an increased risk for
developing breast cancer.
- Not breast-feeding. Women who don't breast-feed have a higher risk of breast
cancer than those who breast-feed. The more months of breast-feeding, the lower
the breast cancer risk.
- Hormones. Female
hormones play a part in some types of breast cancer.
- The use of estrogen-progestin
after menopause for several years or
more increases your risk of developing breast cancer. But within 5 years after
you stop using combined therapy, your risk returns to normal. Long-term use of estrogen alone may increase your risk for
breast and ovarian cancer. 7
- Beginning menstruation before age 12
and beginning
later than age 55 increase a woman's risk of
breast cancer. The years when you have a menstrual cycle are your high-estrogen
years. Experts think that the longer you have higher estrogen, the more risk
you have for breast cancer.8
- Having extra
body fat and drinking alcohol both lead to higher levels of estrogen in the
body. Especially after menopause, when your estrogen levels are naturally low,
this raises your breast cancer risk.8
For more information about your personal risk level, go
to www.cancer.gov/bcrisktool.