- GENDER: Women have a far greater risk of breast cancer than
men. The disease is about 100 times more common among women than men.
- GENETIC RISK FACTORS: Recent studies have shown that 5 percent
to 10 percent of breast cancer cases are hereditary and result from
mutations (changes) of the BRCA1 and BRCA2 genes. About 50 percent
-60 percent of women with inherited BRCA1 or BRCA2 mutations will
develop breast cancer by the age of 70. Women with these inherited
mutations also have an increased risk for developing cancer of the
- PERSONAL HISTORY OF BREAST ABNORMALITIES: Two breast tissue
abnormalities -- ductal carcinoma in situ (DCIS) and lobular carcinoma
in situ (LCIS) -- are associated with increased risk for developing
an invasive breast cancer. A woman with cancer in one breast has a
3- to 4-fold increased risk of developing a new cancer in the other
- BREAST CANCER AMONG RELATIVES: Having one first-degree relative
(mother, sister, or daughter) with breast cancer approximately doubles
a woman's risk, and having two first-degree relatives increases her
risk 5-fold. Risk is also higher among women whose close blood relatives
have this disease. Blood relatives can be from either the mother's
or father's side of the family.
- AGE: The risk of developing breast cancer increases with
age. About 77 percent of women with breast cancer are over the age
of 50 at the time of diagnosis.
- AGE AT FIRST LIVE BIRTH: Women who had their first full-term
pregnancy after age 30 and women who have never borne a child have
a greater risk of developing breast cancer.
- MENSTRUAL PERIODS: Women who started menstruating at an
early age (before age 12) or who went through menopause at a late
age (after age 50) have a slightly higher risk of breast cancer.
- BREAST BIOPSIES: Women who have had breast biopsies have
an increased risk of breast cancer, especially if the biopsy showed
a change in breast tissue known as atypical hyperplasia. These women
are at increased risk because of whatever prompted the biopsies, NOT
because of the biopsies themselves.
- ALCOHOL: Use of alcohol is clearly linked to increased risk
of developing breast cancer. Women who have 2 to 5 drinks daily, have
about 1.5 times the risk of women who drink no alcohol. Alcohol is
also known to increase the risk of developing cancers of the mouth,
throat, and esophagus.
- RACE: White women have greater risk of developing breast
cancer than Black women (although Black women diagnosed with breast
cancer are more likely to die of the disease).have greater risk of
developing breast cancer than Black women (although Black women diagnosed
with breast cancer are more likely to die of the disease).
- SMOKING: While no studies have yet linked cigarette smoking
to breast cancer, smoking affects overall health and increases the
risk for many other cancers, as well as heart disease.
- OBESITY AND HIGH-FAT DIETS: Obesity (being overweight) has
been suggested as a breast cancer risk in all studies, especially
for women after menopause which usually occurs at age 50.
Sources: The National Cancer Institute and the American