One in eight American women will be diagnosed with breast cancer during their lifetimes. Of the women who get it, one out of five will die from it.
Understandably, given these statistics, many women worry about their chances of getting breast cancer. Some women with high risk factors, such as having close relatives who have had breast cancer, go through extra screenings. Some even consider preventative removal of their breasts.
We know that more cases of breast cancer are occurring than fifty years ago. Unfortunately, a whopping 70% of these breast cancer cases are not associated with any known breast cancer risk factors. Scientists are searching for answers.
Everyday chemicals can act like hormones
Over the last decade, scientists have established that some of the chemicals women exposed to can affect their chances of getting breast cancer. For example, certain chemicals called endocrine disruptors can interact with our biology by mimicking the hormones our bodies normally produce (the technical term is the endocrine system). Some of these interactions are thought to increase the chances of getting breast cancer.
How much should we worry about endocrine disruptors? Well, exposure data indicates that we ought to be fairly concerned.
Endocrine-disrupting chemicals are all around us. They are used in everyday products like detergents, antibacterial soaps, plastic containers, air freshener sprays and flame-resistant furniture. We take in these chemicals through our skin, through the air we breathe, and even through chemically contaminated food.
Everyday chemicals are affecting young girls
Phthalates are a group of chemicals produced in huge amounts, exceeding 470 million pounds per year. Phthalates can be found in products made from polyvinyl chloride (PVC) plastic, like shower curtains and flooring. They are also found in varnishes, paints, medical devices like IV tubing and blood bags, and more.
Certain phthalates are endocrine disruptors and have been linked to early puberty and breast development in girls. Research has shown an association between early puberty and breast cancer.
Everyday chemicals can affect our health even before we’re born
Scientists have found that it's especially problematic when a developing fetus is exposed to certain chemicals. In studies on mice, prenatal exposure to the chemical bisphenol A (BPA) led to harmful effects that persisted over a lifetime. Specifically, mice exposed to BPA while still in the womb and in the earliest stages after birth had greater sensitivity to the hormone estrogen during puberty.
The authors of this study note that changes in estrogen levels are a known, central risk factor for breast cancer and that increased sensitivity to estrogen may be of concern.
Everyday chemicals can make it harder to fight cancer
For women already diagnosed with breast cancer, toxic chemicals can do further damage. For example, a number of alkylphenols, chemicals found in detergents and cleaners, and BPA have been shown to stimulate faster division and growth of mammalian breast cancer cells.
BPA may also confer “chemoresistance,” which can make cancer treatments like chemotherapy and other anti-cancer drugs less effective. Scientists have found that breast cancer cells respond less well to chemotherapy treatments after having been exposed to BPA. This has serious implications for the chemotherapy treatment of breast cancer patients who have been exposed to BPA.
Unfortunately, almost everyone is regularly exposed to BPA. The Centers for Disease Control’s biomonitoring data reveals that BPA is present in more than 90% of Americans.
Why are all these chemicals in our bodies?
If we know these chemicals can cause us harm, why isn’t the government protecting us from them?
This year marks the 35th anniversary of one of our most inefficient and ineffective laws: The Toxic Substances Control Act, or TSCA. Enacted in 1976, this law grandfathered in 60,000 already existing chemicals without requiring any assessment of their safety. There are now over 80,000 chemicals on EPA’s chemical inventory. Unfortunately, persistent deficiencies in TSCA have resulted in EPA being able to require testing on only around 200 of them.
For the great majority of chemicals available for use, then, we are left in the dark as to how they’re being used, who’s being exposed, and what harm they might be causing—whether we're talking about breast cancer or other conditions, such as obesity, infertility and Alzheimer’s, for which evidence is also mounting that links them to chemical exposures.
We need a better law: the Safe Chemicals Act
This fall, Congress is likely to take up the Safe Chemicals Act of 2011. This legislation would vastly improve TSCA, giving us much stronger protection against toxic chemicals. Chemical manufacturers would have to provide basic safety data on their chemicals. New chemicals would be assessed for safety before they are allowed onto the market and into the products we buy.
Unfortunately, effective chemicals policies weren’t available for the 40,000 women who died of breast cancer in the past year. But for those of us lucky enough to be free of it or fighting it, for the babies not yet born and the young girls who haven’t made it to puberty yet—we can and need to do better.
Tell your Senators now how important it is to support the Safe Chemicals Act.
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Labat, Vaillant, Sheridan, Pal, Wu, Simpson, Yasuda, Smyth, Martin, Lindeman and Visvader. “Control of mammary stem cell function by steroid hormone signaling.” Nature 2010.
LaPensee, Tuttle, Fox, and Ben-Jonathan. “Bisphenol A at Low Nanomolar Doses Confers Chemoresistance in Estrogen Receptor-α–Positive and –Negative Breast Cancer Cells.” Environmental Health Perspectives, February 2009. 117(2): 175–180.
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