Causes

Causes of Breast Cancer

Some breast cancer risk factors are not in your control, but you may have the power to minimize others. Our doctors are advancing research on the causes of breast cancer and what may make one woman more likely to develop it over another. If you suspect you may be at a higher risk for breast cancer based on your family history, we offer full services for breast cancer risk assessment and screening to help you monitor your health.

Risk Factors that Cannot Be Changed

Gender:

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

Age:

Two out of three women with invasive cancer are diagnosed after age 55.

Race/ethnicity:

Caucasian women develop breast cancer slightly more often than African-American women.

Family history and genetic factors:

Your breast cancer risk increases if you have a close relative, such as a mother or sister with breast or ovarian cancer.

Menstrual cycles that began before age 12:

Women whose periods began early have a longer lifetime exposure to estrogen, which is linked to an increased risk of breast cancer.

Menopause that began after age 55:

Late menopause also results in a longer lifetime exposure to estrogen, increasing a woman's risk of developing breast cancer.

Dense breast tissue:

Older women with dense breast tissue, defined by a mammogram, are at increased risk. The cause of this is not currently well understood.

Lifestyle-Related Risk Factors

• Alcohol consumption of more than one drink per day
• Long-term, postmenopausal hormone replacement therapy (HRT)
• Not having children or having your first child after age 30
• Physical inactivity
• Use of oral contraceptives in the past 10 years
• Weight gain and obesity, especially after menopause

Male Breast Cancer Risk Factors

• Age
• Radiation exposure
• Estrogen treatment
• Diseases, such as cirrhosis or Klinefelter's syndrome
• Heavy alcohol intake
• Weight gain A family history of female relatives with breast cancer