A large-scale international study claims that breastfeeding is associated with a reduced risk of developing aggressive breast cancer known as ‘hormone-receptor negative’ – by about 20 percent.

This meta-analysis is a coordinated study between Breastcancer.org, Icahn School of Medicine at Mount Sinai, Washington University, St. Louis and the American Cancer Society.

Aggressive Types Of Breast Cancer

Hormone-receptor-negative (HRN) breast cancers are more likely to have aggressive and life-threatening consequences. It is generally diagnosed in women from American or Sub-Saharan African descent who are under 50 years of age, as well as women with the BRCA1 gene mutation. Other factors, such as obesity and multiple early pregnancies also increase the risk of developing HRN breast cancer, and these women are consequently less likely to breastfeed.

HRN breast cancer lacks the receptors for hormones such as estrogen or progesterone, and about two-thirds of these cancers also lack receptors for HER2 (human epidermal growth factor receptor 2) or or HER2, which are called triple negative (TN) cancers. Since they lack the above mentioned receptors, these cancers do not respond to most medicines, including tamoxifen, aromatase inhibitors, Herceptin, and Perjeta.

Moreover, HRN and TN are most often fatal because they are usually diagnosed at later stages, are less responsive to treatments, and are less likely to be cured using current therapies.

Promoting Breastfeeding As A Possible Preventive Strategy

“Increasing evidence to sustain the long-term protection by breastfeeding against many aggressive subtypes of breast cancer is very encouraging and actionable”, stated Marisa Weiss, M.D., president and founder, Breastcancer.org, and director of breast health outreach, Lankenau Medical Center. “Breastfeeding is a relatively accessible, low-cost, short-term strategy that yields long-lasting natural protection”.

Lowers The Risk Of Breast Cancer

These findings highlight the need to promote and reinforce public health strategies that directly guide women and girls about the benefits of breastfeeding for themselves and the fetus. Moreover, removing biases and taboos related t breastfeeding from the homes, workplace and community is also essential.

“Pregnant women and young mothers are highly receptive. They must be motivated to make healthy choices and encouraged to breastfeed, for their breast health and their children’s health”, explained Paolo Boffetta, M.D., Associate Director for Population Sciences at the Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai. The study was published in Annals of Oncology.