EXECUTIVE SUMMARY

Breast cancer is the most common cancer in American women, according to the American Cancer Society. In 2019, an estimated 268,600 new cases of invasive breast cancer were diagnosed among women.

About one in three breast cancer cases could be prevented by lifestyle modifications such as weight management, exercise, diet, and alcohol consumption, according to a recent presentation at the North American Menopause Society 2019 Annual Meeting.

Breast cancer prevention recommendations from the World Cancer Research Fund and the American Institute for Cancer are available to aid clinicians.


Breast cancer is the most common cancer in American women, according to the American Cancer Society. In 2019, an estimated 268,600 new cases of invasive breast cancer were diagnosed among women.1

About one in three breast cancer cases could be prevented by simple lifestyle modifications to weight management, exercise, diet, and alcohol consumption.2 During the North American Menopause Society 2019 Annual Meeting, Juliana Kling, MD, MPH, a menopause specialist at the Mayo Clinic in Scottsdale, AZ, outlined several breast cancer prevention recommendations from the World Cancer Research Fund and the American Institute for Cancer Research to aid clinicians.

“Given the magnitude of breast cancer occurrence and the accumulated evidence supporting prevention as the most cost-effective, long-term strategy for reducing breast cancer risk, lifestyle education centered on the American Institute for Cancer Research cancer prevention recommendations should be a core component of routine patient visits,” Kling said in a statement.3

The World Cancer Research Fund and the American Institute for Cancer Research updated their breast cancer prevention recommendations in 2018, adjusting for menopause status when possible. Researchers examined modifiable risk factors, such as exercise, diet, and alcohol.4

As of 2015-2016, the National Center for Health Statistics at the CDC estimated that 41.1% of U.S. women age 20 years and older were obese.5 Postmenopausal women have a 1.5 to 2.0 times increased risk of breast cancer if they are obese. Body fat may increase the susceptibility to cancer as a result of hyperinsulinemia, increased estradiol, and inflammation.6

Physical activity may have a role in preventing breast cancer. Research indicates that five hours per week of brisk walking can reduce the risk.7 The American Cancer Society advises that adults engage in 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity each week.8

What About Alcohol?

In a 2011 large, prospective cohort study drawn from the Nurses Health Study, researchers observed an association between low levels of alcohol consumption and breast cancer risk. Cumulative average alcohol consumption over long periods of time, and both drinking earlier and later in adult life were independently associated with breast cancer risk.9 The American Cancer Society advises that women drink no more than one alcoholic beverage per day. A drink is defined as 12 ounces of beer, five ounces of wine, or 1.5 ounces of hard liquor.8

Research surrounding diet and breast cancer risk is ongoing. Study results indicate that a diet rich in vegetables, fruit, poultry, fish, and low-fat dairy may be of benefit.10 Researchers from the Women’s Health Initiative clinical trial studied the effects of dietary modification in 49,000 postmenopausal women with no previous history of breast cancer. They found that women who followed a balanced diet that was low in fat and included daily servings of fruits, vegetables, and grains had a 21% lower risk of death from breast cancer than women in the control group.11

REFERENCES

  1. American Cancer Society. Breast Cancer Facts & Figures 2019-2020. Atlanta: American Cancer Society, Inc. 2019.
  2. Kling J. Breast cancer prevention: The importance of lifestyle. Presented at the North American Menopause Society (NAMS) 2019 Annual Meeting, Chicago, September 2019.
  3. North American Menopause Society. Simple lifestyle modifications key to preventing large percentage of breast cancer cases, Sept. 24, 2019. Available at: https://bit.ly/2QNnBFV.
  4. World Cancer Research Fund/American Institute for Cancer Research. Diet, nutrition, physical activity, and cancer: A global perspective. Continuous Update Project Expert Report 2018. Available at: https://bit.ly/2TkpVFN.
  5. Hales CM, Carroll MD, Fryar CD, et al. Prevalence of obesity among adults and youth: United States, 2015-2016. NCHS Data Brief 2017;288:1-8.
  6. Rohan TE, Heo M, Choi L, et al. Body fat and breast cancer risk in postmenopausal women: A longitudinal study. J Cancer Epidemiol 2013;754815.
  7. Eliassen AH, Hankinson SE, Rosner B, et al. Physical activity and risk of breast cancer among postmenopausal women. Arch Intern Med 2010;170:1758-1764.
  8. American Cancer Society. Can I lower my risk of breast cancer? Fact sheet. Available at: https://bit.ly/3a7CHxl.
  9. Chen WY, Rosner B, Hankinson SE, et al. Moderate alcohol consumption during adult life, drinking patterns, and breast cancer risk. JAMA 2011; 306:1884-1890.
  10. Laudisio D, Barrea L, Muscogiuri G, et al. Breast cancer prevention in premenopausal women: Role of the Mediterranean diet and its components. Nutr Res Rev 2019; doi: 10.1017/S0954422419000167.
  11. Chlebowski RT, Aragaki AK, Anderson GL, et al. Low-fat dietary pattern and long-term breast cancer incidence and mortality: The Women’s Health Initiative randomized clinical trial. Presented at the 2019 ASCO Annual Meeting, Chicago, June 2019.