Risk Factors for Breast Cancer

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:

• gender
  Breast cancer occurs nearly 100 times more often in women than in men.

• aging
  A majority of cases occur after age 50.

• 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

• previous breast biopsy in which the tissue showed atypical hyperplasia

• menstrual periods that began early in life

• menopause that began later in life

The most frequently cited lifestyle-related risk factors:

• smoking
  
  
• not having children, or first child after age 30
  
  
• oral contraceptives
  
  
• obesity and a high-fat diet
  
  
• physical inactivity
  
  
• alcohol
  
  
• 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:

To learn more about women's health, and specifically hormone replacement therapy, the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH) launched the Women's Health Initiative (WHI) in 1991. The hormone trial had two studies: the estrogen-plus-progestin (HRT) study of women with a uterus and the estrogen-alone (ERT) study of women without a uterus. Both studies were concluded early when the research showed that hormone replacement did not help prevent heart disease and it increased risk for some medical problems.

The WHI recommends that women follow the Food and Drug Administration (FDA) advice on hormone (estrogen-alone or estrogen-plus-progestin) therapy. It states that hormone therapy should not be taken to prevent heart disease.

These 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.

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