Breastfeeding’s Role in Breast Cancer Risk Reduction

I’m often asked questions regarding breast health, specifically breast cancer risk and breastfeeding. Most patients like to go to ‘Dr. Google’ when researching information. The intent of this topic is to summarize the benefits that breastfeeding provides and answer a commonly asked question, “does breastfeeding lower your breast cancer risk?” Overall, female hormones (estrogen and progesterone) are known to ‘fertilize’ certain breast cancers. A woman’s lifetime exposure to hormones can promote breast cancer cell growth. Studies show that breastfeeding can reduce the risk of breast cancer, especially in premenopausal women. The benefit is seen in hormone driven (estrogen or progesterone receptor positive) and hormone deprived (estrogen and progesterone negative) breast cancers. Pregnancy protects the breast because there is no ovulation during this time- your hormones are decreased in the system. The decreased number of menstrual cycles reduces your exposure to hormones because the body is focused on the growing baby, not trying to create another! Once your bundle of joy is here, studies show that women who breastfeed have a lower risk of breast cancer compared to those who choose not to breastfeed. Breastcancer.org states how breastfeeding protects the breast health:

1. It limits breast cells’ ability to misbehave.
2. There are fewer menstrual cycles while breastfeeding due to lower estrogen levels.
3. There’s better overall nutrition with a healthier lifestyle (e.g. less smoking/alcohol).

Most women who breastfeed experience changing hormone levels that delay their menstrual period, which reduces the lifetime breast tissue exposure to hormones. According to the American Institute for Cancer Research and World Health Organization, breastfeeding for at least a 6-month duration demonstrates health benefits and decreases your cancer risk. According to a study by the “Collaborative Group on Hormonal Factors in Breast Cancer,” researchers found that for every 12 months a woman breastfed, her risk of breast cancer decreased by 4.3%. The 12-month time period could be with either one child or the total for several children! Despite the lower risk, there are changes in the breast that can occur with breastfeeding: engorgement, mastitis, abscess, cysts, and in rare cases, breast cancer. A woman should see her doctor if the mass does not go away, continues to grow, does not move, or causes skin to change (e.g. dimpling or inflammation). A woman should speak with her doctor directly if they have any concerns about their breast health.

Authored by Anjeanette Brown, MD.

Dr. Anjeanette Brown is a board-certified general surgeon with a specialty in breast health. She is a member of the American College of Surgeons, Society of Surgical Oncology and The American Society of Breast Surgeons. Dr. Brown is passionate about patient care and teaching others about early detection and the treatment of breast cancer. References: https://www.breastcancer.org/ https://www.aicr.org/ https://www.who.int/ https://www.mdanderson.org/