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Risk Factors that Contribute to Your Overall Risk of Breast Cancer

There are many factors that contribute to a woman’s risk of breast cancer. The top two risk factors associated with breast cancer are 1) being a woman and 2) age. As we grow older, our risk for breast cancer increases. Approximately 8 out of 10 breast cancers occur in women age 50 and over.

There are many other factors that contribute to the overall risk of developing breast cancer:

  • The third most significant risk factor is having a personal history of breast cancer.
  • A diagnosis of ductal or lobular carcinoma may increase a woman’s risk of developing invasive breast cancer.
  • Women who have been diagnosed with ovarian, colon or endometrial cancer may be at an increased risk of breast cancer.

Most fibrocystic changes do not increase a woman’s risk of developing breast cancer. However, fibrocystic changes containing “cellular atypia” (change in the normal appearance) can increase your risk. Cellular atypia can only be diagnosed by a pathologist through breast biopsy.

  • Starting periods at less than 12 years of age; late menopause — age 55 years or older. The more menstrual periods a woman has in her lifetime, the more the risk.
  • Never carrying a pregnancy to full term.
  • First pregnancy at age 30 or older.
  • Never breastfed a child.
  • Oral contraceptive use or hormone therapy.
  • Previous chest irradiation for another type of cancer, especially at a young age.
  • Risk appears to increase when a first-degree relative (mother, sister or daughter) is diagnosed with breast cancer at an age less than 40 and/or has had breast cancer in both breasts.
  • Breast cancer in two or more family members may increase risk.
  • A family history of ovarian, endometrial, colon and/or prostate cancer may also increase breast cancer risk.
  • When looking at family history, it is important to consider both maternal and paternal sides of the family.
  • Certain gene defects inherited from parents (i.e. BRCA gene mutation).

Most breast cancers (80%) are diagnosed in women with no family history of cancer. Most breast cancers are due to environment and heredity.

  • Obesity – because the body makes some of its estrogen in fatty tissue, obese women are more likely to have higher levels of estrogen in their bodies. High levels of estrogen may be the reason that obese women have an increased risk of breast cancer.
  • Lack of physical exercise.
  • Excess use of alcohol may also increase the risk of breast cancer (consumption of one or more alcoholic beverages daily).
  • Hormone therapy – women who take hormone therapy (estrogen plus progestin) are at greater risk. Women who use estrogen long term (greater than 10 years) are at higher risk.

Next Steps

There are additional imaging recommendations and screening options for women found to be at higher risk to help monitor their breast health. Those options and recommendations vary by person and your circumstances should be discussed with your provider. The best first step is to have a mammogram. Contact a center near you to schedule a mammogram or find out more.