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Breast Cancer 

Causes, Risk Factors, & Symptoms

Cancer is a result of damaged DNA.  The cause of the damage is most often a combination of biological and environmental factors. While the exact cause is unknown, some risk factors have been shown to increase the risk of developing breast cancer.

Risk factors:

  • Being a woman

  • Aging

  • Certain gene mutations

  • A personal or family history of breast cancer

  • Dense breast tissue

  • Getting your period before age 12

  • Starting menopause after age 55

  • Radiation treatment to the chest

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

  • Drinking alcohol

  • Being obese or overweight

  • Being inactive

  • Some types of hormonal birth control medications

  • Taking certain hormone therapy medications

A thorough list of risk factors for breast cancer is available on the American Cancer Society's website.9


Various signs and symptoms might indicate that you have breast cancer. If you have any of these signs or symptoms, make an appointment with your doctor as soon as possible.

  • A lump or thickening in your breast or armpit
  • Changes in the size or shape of your breast
  • Pus-like or bloody fluid from the nipple
  • Dimpling, redness, or an inward-turned nipple
  • Skin irritation on or around your breast


  1. (WebMD: Breast Cancer Health Center)
  2. (Mayo Clinic: Breast Cancer)
  3. (National Cancer Institute: Cancer Statistics) and (National Cancer Institute: SEER Stat Fact Sheets: Female Breast Cancer)
  4. (World Health Organization: Cancer Fact Sheet)
  5. (MedlinePlus: Breast Cancer)
  6. (National Cancer Institute: Breast Cancer—Health Professional Version)
  7. (National Cancer Institute: Breast Cancer—Patient Version)
  8. (American Cancer Society: Breast Cancer)
  9. (American Cancer Society: Breast Cancer Risk Factors)
  10. (American Cancer Society: Guidelines for the Early Detection of Cancer)
  11. (American Cancer Society: Cancer Glossary)
  12. (National Cancer Institute: Staging)
  13. (American Cancer Society: Breast Cancer in Men Key Statistics)
  14. (MedlinePlus definition of general anesthesia)