Lowering the Risk of Future Breast Cancer in Prepubescent Girls

We recently hosted a discussion led by Dr. Sharima Rasanayagam, Director of Science with Breast Cancer Prevention Partners (BCPP). BCPP is the only national organization focused on the prevention of breast cancer and is unique in its focus on a science-based approach to prevention.

Throughout the discussion, Dr. Rasanayagam walked us through the known causes of breast cancer outside of genetics, which accounts for less than 20% of breast cancer cases. She also explained specifically why prepubescent girls are especially at risk of outside exposures.

Higher Risk of Future Breast Cancer in Prepubescent Girls

The breast is the only organ, other than the brain, that isn’t fully developed at birth. It is also the ONLY organ that continues to develop after childhood. The main stages of development are pre-birth, puberty, and pregnancy and lactation. Each of these developmental stages can be affected by the hormones in our environment. That is why BCPP worries about the hormone disruptors found in our environment that look like estrogen to our bodies. The breast is particularly affected by these chemicals as the prolific growth in breast tissue during these developmental stages is precisely controlled by hormones.

It is not only exposures to large quantities of hormone disruptors that matter, as some might assume. Due to the preciseness of hormones’ control on our bodies, very tiny amounts of exposure have been shown to have an effect. Mixtures also matter, as we are not exposed to chemicals one at a time. We are confronted with a soup of chemicals daily, and it is not known how these interact with each other. Most chemical safety tests have been performed with a single chemical at a time, and until recently, only on male rats.

Environmental Exposures

One result of changes in our lifestyle and environment can be seen is the earlier ages of puberty. In the past forty years, the average age of menstruation has dropped by 6 months. The average age at which girls begin to develop breasts has dropped by TWO YEARS! Thus, the timeframe of puberty has also gotten longer, leaving girls exposed to outside forces on their development for even longer as well. There is a longer timeframe in which the division of cells is happening, in which those cells are vulnerable to developmental disturbances.

One reason hormone disrupting chemicals may have more of an effect on breast tissue than menstruation is that breast development seems to be more sensitive to estrogen signals than menstruation. Cleaning and personal care products that are filled with hormone disruptors (and often not even disclosed, rather hidden as “fragrances”) could be adding to this environmental change.

Risks Resulting from Early Puberty

Girls who develop earlier suffer both long and short-term effects. In the short term, they have higher rates of anxiety and depression. In the long term, they have higher rates of reproductive related cancers. For every earlier year that a girl gets her period, her risk of breast cancer is increased by 5%. That’s up to 30% for girls getting their period at age 8 vs. 14.

What Can You Do to Reduce Risk?

The biggest thing a parent can do to decrease the risk of early puberty is keep their children at a healthy weight. The percent of children who are obese has greatly increased over the last 30 years. Fat cells produce enzymes that can take testosterone (produced by the adrenal gland), and convert it to estrogen. There are also a number of chemicals, some commonly used in pesticides, that are obesogens. These chemicals have been shown to make rats who are otherwise healthy become obese. Limiting red and processed meat for children is also suggested. Currently, most American beef is not allowed to be sold in Europe because of the added hormones in the U.S. supply.

Social stresses can also be a trigger for early puberty. Absent biological fathers and depressed mothers were correlated with increases.

Other factors, like an individuals’ genetics and stress level can have an effect on breast cancer rates. Lifetime exposure to estrogen (more cycles) increases the risk of breast cancer. Having babies earlier and more of them decreases the risk. Breastfeeding also reduces the risk. Smoking cigarettes and drinking alcohol increase the risk of breast cancer.

What Breast Cancer Prevention Partners are Doing

Breast Cancer Prevention Partners has made huge strides towards protecting us from these risk factors. For example, they recently convinced the government of California to require ingredient labeling of cleaning products. You will see these disclosures, and hopefully some resulting ingredient changes, over the next couple of years. Read more in our article, Clear Labels for Cleaning Products (Finally!)

To learn more about BCPP’s work and how to support them, visit. www.bcpp.org.