Skip to Content

Blog


Breast Cancer Risk Factors and the Genetics of Breast Cancer

Understanding the risks of breast cancer and how to control your risk factors is an important part of awareness. It is also important to understand breast cancer genetics if you have been diagnosed with breast cancer or have a family member who has breast cancer.

Breast cancer is more common in obese patients and in patients who smoke. It is also more common in patients who take estrogen or progesterone hormone replacement; HRT (hormone replacement therapy) increases breast cancer risk by 25%. Alcohol also increases breast cancer risk. More than three or four alcoholic beverages per week increase breast cancer risk by 15%. Prior radiation in the breast region also increases breast cancer risk. Conversely, moderate exercise decreases breast cancer risk by 15-25% and breastfeeding also decreases breast cancer risk.

Genetic testing for breast cancer has allowed many women to control their risk of future breast cancers with prophylactic mastectomies. Women at high risk for breast cancers that may benefit from genetic testing include those with:

  • a first or second degree relative who were diagnosed before the age of 50,
  • any male first or second degree relative diagnosed with breast cancer,
  • two or more breast cancers in the same first or second degree relative,
  • two or more relatives on the same side of the family with breast cancer,
  • breast cancer and ovarian cancer on the same side of the family,
  • a family member with a “triple negative” breast cancer diagnosed before the age of 60,
  • a first or second degree relative with the BRCA gene mutation.

Patients with the BRCA 1 mutation have a 72% increased risk of breast cancer and a 44% increased risk of ovarian cancer, while those with the BRCA 2 mutation have a 69% increased risk of breast cancer and a 17% increased risk of ovarian cancer. Our knowledge of genetics has allowed identification of other genes that increase a woman’s risk of breast cancer including CHEK2, ATM, PTEN, PALB2, and BRIP1. Informed patients can make decisions about how they can lower their cancer risk through prophylactic surgery and other risk reducing strategies such as exercise. Knowledge is power!