Health Library

Health Library

Cancer Types - 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 for any disease can help 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.

  • Race or ethnicity. It has been noted that white women develop breast cancer slightly more often than African-American women. However, African-American women tend to die of breast cancer more often. This 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.

  • Aging. Two out of 3 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. Women with certain benign breast conditions (such as hyperplasia or atypical hyperplasia) have an increased risk of breast cancer. 

  • Dense breast tissue. Breast tissue may look dense or fatty on a mammogram. Older women with high dense breast tissue are at increased risk.

  • Diethylstilbestrol (DES) exposure. Women who took this drug while pregnant (to lower the chance of miscarriage) are at higher risk. The possible effect on their daughters is under study.

  • Early menstrual periods. Women whose periods began early in life (before age 12) have a slightly higher risk of breast cancer.

  • Late menopause. Women are at a slightly higher risk if they began menopause later in life (after age 55).

The most frequently cited lifestyle-related risk factors:

  • Not having children, or having your first child after age 30

  • Recent use (within 10 years) of oral contraceptives

  • Physical inactivity

  • Alcohol use (more than 1 drink per day)

  • Long-term, postmenopausal use of combined estrogen and progestin (HRT)*

  • Weight gain and obesity, especially 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 related to menopause 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 nonestrogen 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 with their doctor.

Risk Factors for Breast Cancer - WellSpan Health

Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Online Medical Reviewer: Moloney Johns, Amanda, PA-C, MPAS, BBA
© 2014 WellSpan Health. All Rights Reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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