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). However, men can also get breast cancer. Certain lifestyle factors affect the risk for breast cancer: 

  • physical activity
  • night shift work
  • smoking
  • alcohol use
  • eating red meat (>5 servings/week)

Obesity and radiation exposure to the chest also increase the risk for breast cancer.

Breast cancer is more common among women who:
  • Are older. As women get older their chances of getting breast cancer increase. 
  • Have dense breast tissue or proliferative breast lesions (e.g., atypical hyperplasia)
  • Started their periods early (before age 12) or had menopause late (after age 55)
  • Have no children or pregnancy at an older age (after age 30) 
  • 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 all play a role in how breast cancer develops. 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 could increase breast cancer risk. Contraceptive use in women with low or moderate dose estrogen does not increase breast cancer risk. 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 by doing a special kind of x-ray called mammogram. High risk women may also need screening MRI (magnetic resonance imaging) scans, which are more sensitive than a mammogram. Many women notice lumps in the breast or the armpit and seek medical attention. Although not all lumps are cancers, it's very important that you talk your doctor about it. Depending on the size and consistency of the lump, your doctor can order different 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?

When breast cancer is found and treated early, it is most often curable. 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 (for women before menopause)
  • immunotherapy
  • combination of treatments above

Some forms of breast cancer grow with estrogens. An anti-estrogen hormone therapy, such as selective estrogen receptor modulators (tamoxifen/raloxifene), blocks the effect of female hormones on the cancer. Another type of anti-estrogen therapy is the aromatase inhibitors (anastrozole, letrozole, or examestane) which prevent the body from making female hormones. These anti-estrogen therapies can cause bone loss. Your doctor will need to monitor for this and potentially give you treatment to reduce the risk of fractures. 

If you are at high risk for developing breast cancer, you can take tamoxifen or raloxifene 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, adopting healthier eating habits (avoid red meat, eat fruits/vegetables), reducing alcohol and quitting smoking may be helpful in preventing breast cancer. Planning your first child before the age of 30 and breastfeeding for at least six months could help in reducing your risk of getting breast cancer. 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 least since age 40. Talk with your doctor 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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