What is a risk factor?
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors.
Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
What are the risk factors for breast cancer?
Any woman may develop breast cancer. However, the following risk factors may increase the likelihood of developing the disease.
Risk factors that cannot be changed:
Breast cancer occurs nearly 100 times more often in women than in men.
It has been noted that Caucasian women develop breast cancer slightly more often than African-American women. However, African-American women tend to die of breast cancer more often. This is may be partly due to the fact that African-American women often develop a more aggressive type of tumor, although why this happens is not known. The risk for developing breast cancer and dying from it is lower in Hispanic, Native American, and Asian women.
Two out of three women with invasive cancer are diagnosed after age 55.
personal history of breast cancer
previous breast irradiation
family history and genetic factors
Having a close relative, such as a mother or sister, with breast cancer increases the risk. This includes changes in certain genes such as BRCA1, BRCA2, and others.
benign breast disease
dense breast tissue
Breast tissue may look dense or fatty on a mammogram. Older women with dense breast tissue are at increased risk.
diethylstilbestrol (DES) exposure
Women who took DES while pregnant (to lower the chance of miscarriage) are at higher risk. The possible effect on their daughters is under study.
previous breast biopsy in which the tissue showed atypical hyperplasia
menstrual periods that began early in life (before age 12)
menopause that began later in life (after age 55)
The most frequently cited lifestyle-related risk factors:
not having children, or first child after age 30
long-term, post-menopausal use of combined estrogen and progestin (HRT)
weight gain and obesity after menopause
Environmental risk factors:
Exposure to pesticides, or other chemicals, is currently being examined as a possible risk factor.
Hormone replacement therapy update:
Hormone (estrogen-alone or estrogen-plus-progestin) products are approved therapies for relief from moderate to severe hot flashes and symptoms of vulvar and vaginal atrophy. Although hormone therapy is effective for the prevention of postmenopausal osteoporosis, it should only be considered for women at significant risk of osteoporosis who cannot take non-estrogen medications. The FDA recommends that hormone therapy be used at the lowest doses for the shortest duration needed to achieve treatment goals.
Postmenopausal women who use or are considering using hormone therapy should discuss the possible benefits and risks to them with their physicians.