Breast Cancer


Who is at risk for breast cancer?

Breast cancer is one of the most common cancers in U.S. women (1 in 8 women). Obesity, lifestyle (inactivity, alcohol use, smoking, night shift work), and radiation exposure to the chest also increase risk.

Breast cancer is more common among women who:
  • Are older (older than 70)
  • Who started their periods early (before age 12)
  • Have no children or delayed pregnancy (after age 30)
  • Who never breastfed
  • Have used combination hormone therapy (estrogen plus progestin) for more than five years during menopause
  • Have a mother, sister, or daughter who has had breast cancer

What causes breast cancer?

Your genes, hormones, lifestyle, and environment work together to lead to breast cancer, but we don’t know exactly how. We know that estrogen (the major female hormone) and progestin (a synthetic form of progesterone, another female hormone) can cause breast tissue to grow faster than normal. While long-term use of estrogen/progestins during menopause has been associated with higher breast cancer risk, contraceptive use in pre-menopausal women with low or moderate dose estrogen has not. Certain genes (such as BRCA1 or BRCA2) greatly increase breast cancer risk.

How is breast cancer diagnosed?

The most common way to find breast cancer is through a breast exam or mammogram (x-ray). High risk women may also need screening MRI (magnetic resonance imaging) scans, which are more sensitive than a mammogram.Not all lumps are cancer. If you find a lump, or a lump that has changed in size or consistency, your doctor may order a variety of tests.

These tests can include:

  • A mammogram
  • A breast ultrasound
  • A sample of cells from the lump (called a fine needle aspirate)
  • A sample of a piece of tissue from the lump (called a core biopsy)

Possible Symptoms of Breast Cancer

  • A lump, especially if hard and immobile with irregular borders 
  • A change in the size or shape of the breast
  • Puckering, dimpling, and redness of the breast skin
  • Nipple discharge from one breast but not the other
  • Bloody discharge from a nipple

How is breast cancer treated?

Treatment for breast cancer depends on the type and the stage of the cancer. Typical treatments include surgery, radiation therapy, chemotherapy, anti-estrogen hormone therapy, ovarian suppression therapy, targeted monoclonal antibody therapy, or a combination of these. Anti-estrogen hormone therapy includes selective estrogen receptor modulators (tamoxifen/raloxifene) which blocks the effect of female hormones on the cancer and aromatase inhibitors (anastrozole, letrozole, or examestane) which prevent the body from making female hormones.

If you are at high risk for developing breast cancer, tamoxifen or raloxifene can also be taken to prevent the disease. Your doctor will work with you to determine the best treatment option for you.

What you can do to prevent breast cancer and to see if you have it?

Lifestyle changes, such as regular exercise, eating fruits/vegetables, and avoiding excess alcohol, daily red meat, or any tobacco smoke exposure, may be helpful in preventing breast cancer. Breastfeeding for at least six months, planning your first child before age 30, limiting night shift work, and avoiding/limiting menopausal hormone therapy may also be protective.

Most breast cancers in the United States are diagnosed after an abnormal screening study. You should have a screening mammogram every year or two, starting no later than age 50. Many health professional organizations recommend starting mammograms at age 40, but individualized decisions are also recommended.

If you are at high risk for breast cancer, you should get an annual mammogram and breast MRIs, spaced six months apart, at age 40. Talk with your provider about other screening tests, medications to prevent breast cancer, or genetic testing.

Questions to ask your doctor

  • What is my risk for breast cancer?
  • If I’m at high risk, should I take medication to prevent breast cancer?
  • How often should I do breast self-exams?
  • How often do I need to get a mammogram?
  • Should I see an endocrinologist?
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