Results from a large study underscore earlier research strongly suggesting that black women who breastfeed have a lower risk of hormone-receptor-negative and triple-negative breast cancer.
The research was published in the October 2014 issue of the Journal of the National Cancer Institute. Read the abstract of “Parity, Lactation, and Breast Cancer Subtypes in African American Women: Results from the AMBER Consortium.”
Black women are much more likely than white women to be diagnosed with triple-negative breast cancer.
Triple-negative breast cancer is:
Triple-negative breast cancers can be more aggressive, harder to treat, and more likely to come back (recur) than cancers that are hormone-receptor-positive or HER2-positive. Triple-negative breast cancers don’t usually respond to hormonal therapy medicines or targeted therapy medicines for HER2-positive disease.
Other studies also have shown that breast cancer risk is lower among women who have breastfed one or more babies. Still, not much research has looked at links between breastfeeding and a lower risk of particular types of breast cancer in particular women.
The AMBER Consortium combines four of the United States’ leading studies on black women and breast cancer, involving more than 10,000 women and looking at genetic, biological, reproductive, and behavioral breast cancer risk factors.
In this study, the researchers combined data from four studies involving more than 17,000 black women. In each study the women filled out questionnaires asking about any breast cancer diagnoses and the characteristics of the cancer and diagnosis, as well as the number of children they had and their breastfeeding history.
Women who had been diagnosed with breast cancer were classified into three groups:
- estrogen-receptor-positive (2,446 women)
- estrogen-receptor-negative (1,252 women)
- triple-negative (567 women)
These women were compared to more than 14,000 black women who hadn’t been diagnosed with breast cancer.
The researchers found that compared to black women who had never given birth, black women who had given birth had a higher risk of certain types of breast cancer, specifically a:
- 33% higher risk of estrogen-receptor-negative breast cancer
- 37% higher risk of triple-negative breast cancer
Breastfeeding reduced the risk of estrogen-receptor-negative breast cancer, but not estrogen-receptor-positive breast cancer.
The risk of estrogen-receptor-negative breast cancer went up with each child a black women who didn’t breastfeed had.
In the paper, the researchers said that the results may help explain why black women, who overall have more children but lower breastfeeding rates than white women, are more often diagnosed with estrogen-receptor-negative breast cancer.
If breastfeeding is an option for you, you may want to consider it. Besides possibly lowering your breast cancer risk, breastfeeding gives your child antibodies through the breast milk that can protect him/her from bacterial and viral infections. Still, these are highly individual decisions affected by many factors besides breast cancer risk and whether you are able to breastfeed.
Choosing to breastfeed is a personal decision. For some women, it may be more practical to bottlefeed. Still, if you’re a black women and are considering whether to breastfeed or not, you may want to talk to your doctor about this study. Your doctor or someone in your doctor’s office can give you much more information on breastfeeding and its benefits and refer you to a lactation consultant if you have problems.