Can breast cancer be prevented?

Risk factors that cannot be changed

  1. Being a woman: Breast cancer is about 100 times more common in women than in men. 
  2. Getting older: Most invasive breast cancers are found in women aged 55 and older.
  3. Certain inherited genes: About 5-10% of breast cancer cases are thought to be hereditary. 
  4. Having a family history of breast cancer: Having a first-degree relative (mother, sister, or daughter) with breast cancer almost doubles a woman’s risk. Having 2 first-degree relatives increases her risk about 3-fold. 
  5. Having a personal history of breast cancer: A woman with cancer in one breast has a higher risk of developing a new cancer in the other breast or in another part of the same breast. 
  6. Your race and ethnicity: White women are slightly more likely to develop breast cancer, but breast cancer is more common in African women under 45 years of age. 
  7. Having dense breast tissue: Women with dense breasts on a mammogram have a 1.2-2 times greater risk of breast cancer. 
  8. Certain benign breast conditions: Women diagnosed with certain benign (non-cancer) breast conditions may have a higher risk of breast cancer.
  9. Starting menstruation (periods) before age 12: Women who have had more menstrual cycles because they started menstruating early (before age 12) have a slightly higher risk of breast cancer. 
  10. Going through menopause after age 55 : Women who have had more menstrual cycles because they went through menopause later (after age 55) have a slightly higher risk of breast cancer.
  11. Exposed to radiation to the chest : Women who have been treated with radiation therapy to the chest have a significantly higher risk for breast cancer. 
  12. Exposure to diethylstilbestrol (DES): Women who have used DES to prevent miscarriages are at an increased risk of developing breast cancer. Similarly, women whose mothers took DES during pregnancy may also have a slightly higher risk of breast cancer.

Lifestyle-related breast cancer risk factors

  1. Drinking alcohol: Women who have 2-5 drinks daily have about a 1.5 times greater risk for developing breast cancer. 
  2. Being overweight or obese: Being overweight or obese after menopause can increase breast cancer risk. 
  3. Physical activity: As little as 80 minutes to 2.5 hours per week of brisk walking can reduce a woman’s risk by 18%. 
  4. Having children: Women who have not had children or who had their first child after age 30 have a slightly higher breast cancer risk overall. 
  5. Oral contraceptives/birth control pills and birth control injection: Women using birth control pills or the injection have a slightly higher risk of breast cancer than women who have never used them. Once the intervention is stopped, this risk seems to go back to normal over time. 
  6. Hormone therapy after menopause: Women who use hormone therapy after menopause have an increased risk of breast cancer. 
  7. Chemicals in the environment: Substances found in some plastics, certain cosmetics and personal care products, pesticides and PCBs (polychlorinated biphenyls) seem to have cancer-inducing properties. 
  8. Tobacco smoke: Heavy smoking over a long-time is linked to a higher risk of breast cancer. 
  9. Night work: Women who work at night have an increased risk of breast cancer.
Controversial breast cancer risk factors

  • Antiperspirants
  • Bras
  • Induced abortion
  • Breast implants

Research done by Prof. Dr. Ina Shaw (MMI Holdings and University of Johannesburg) and Prof. Dr. Brandon S. Shaw (University of Johannesburg).

You might want to read more about how to do a breast self-exam.