Breast Cancer Prevention Begins in the Womb

TedSchettlerwritten by Ted Schettler, MD, MPH
Science Director

As breast cancer awareness month ends with its primary emphasis on early detection I’ve been more interested in what we’ve learned about opportunities for prevention. Amidst all the pink ribbons and disagreements about optimal mammography scheduling an important theme seems to be finally taking hold. Although opportunities abound throughout life, breast cancer prevention begins in the womb.

This idea is not new. Twenty-five years ago Dimitri Trichopoulos proposed that breast cancer risk could originate in utero, influenced by maternal hormone levels.[1] Later studies linked hormone and growth factor levels with populations of breast stem cells in umbilical cord blood—a plausible mechanistic connection to cancer risk. A 2011 analysis reported a nearly two-fold increased risk of breast cancer in daughters of women who took estrogenic diethylstilbestrol (DES) during pregnancy before 1971.[2] This year, Barbara Cohn and colleagues reported that the highest maternal levels of the hormone-disrupting pesticide DDT during pregnancy were associated with a nearly four-fold increased risk of breast cancer in their daughters.[3]

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Top 10: 2nd Quarter 2015

The ten biggest news or research stories of the last quarter, in CHE’s view.

  1. Climate Change
    Climate change continues to receive attention, from top-level activities to broad new investigations of health impacts.

    1. Pope delivers strong message on climate change in encyclical ‘Laudato Si’‘: In his much-awaited encyclical on the environment, Pope Francis offered a broad and uncompromising indictment of the global market economy, accusing it of plundering the Earth at the expense of the poor and of future generations. The encyclical: Laudato Si’.
    2. Obama Administration announces actions to protect communities from the health impacts of climate change at White House summit: The White House hosted a first-ever Summit on Climate Change and Health, featuring the Surgeon General, to stimulate a national dialogue on preventing the health impacts of climate change. See the speaker presentations and other videos on the White House blog.
    3. EPA carbon emissions plan could save thousands of lives, study finds: New carbon emissions standards that were proposed last year for coal-fired power plants in the United States would substantially improve human health and prevent more than 3,000 premature deaths per year, according to a new study. The study: US power plant carbon standards and clean air and health co-benefits.
    4. Climate change set to take major toll on economy and children’s health, experts warn: Researchers have only scratched the surface of the complex effects climate change will have on children’s health and the economy, panelists said at a climate change forum at the Woodrow Wilson International Center for Scholars.
  2. Cancer risk from chemical cocktail
    Scientists looked at 85 chemicals not usually considered to have a role in causing cancer and found that 50 could play a part. The chemicals, at everyday exposure levels, were found to support mechanisms in the body that helped cancer to develop. They included chemicals found in items such as mobile phones, detergents and cooking pans, and pesticides used on fruits and vegetables. The study: Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
  3. Weed killers, bee killers, sperm killers?
    Research on a variety of pesticides is finding new effects and driving decisions to reduce use.

    1. Controversial insecticide use rises as farmers douse seeds: Since the early 2000s, US farmers have dramatically increased their use of controversial insecticides suspected of playing a role in the decline of pollinating insects, such as honeybees. The report: Large-scale deployment of seed treatments has driven rapid increase in use of neonicotinoid insecticides and preemptive pest management in U.S. field crops.
    2. Announcing new steps to promote pollinator health: In June 2014, President Obama issued a Presidential Memorandum directing an interagency task force to create a Strategy to Promote the Health of Honey Bees and Other Pollinators. In May, under the leadership of the US Environmental Protection Agency and US Department of Agriculture, the task force released its strategy. A summary and analysis: US plan to help bees focuses on more land.
    3. Pesticides on vegetables and fruit linked to lower sperm counts: A study found that those who consume fruits and vegetables that are known to have the highest quantity of pesticides have sperm counts that are 50 percent lower than those who eat the smallest amount of these items. The study: Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic.
    4. Health Canada looks to re-label weed killer Roundup: Health Canada announced on Monday that it will begin public consultations to update the product label to reduce human and environmental exposure. The consultation webpage: Consultation on Glyphosate, Proposed Re evaluation Decision PRVD2015-01
    5. France bans sale of weedkiller Roundup over UN fears it may be carcinogenic: French Ecology Minister Segolene Royal announced Sunday a ban on the sale of popular weedkiller Roundup from garden centres, which the UN has warned may be carcinogenic.
    6. Europe starts taking glyphosate off the shelves: Switzerland’s two largest retailers, Migros and Coop, have been listening to their customers and are already taking retail products containing glyphosate off their shelves. The Swiss retail withdrawal of glyphosate follows the announcement by German retail giant REWE that it will complete its withdrawal of glyphosate products from its 350 gardening outlets by September this year, at the latest.
    7. Chemical reactions: glyphosate and the politics of chemical safety: The IARC’s evaluation presents a dilemma for regulatory institutions. If they explicitly accept the validity of the IARC’s findings (and therefore acknowledge the choice-laden nature of safety evaluation) this might invite scrutiny and criticism of their own assessments, and regulatory decisions.
  4. Fracking/drilling and health
    Breathing problems, cancer, lower birth weight, earthquakes and other effects inform policy decisions on fracking.

    1. Contamination and geologic effects
      1. Fracking chemicals detected in Pennsylvania drinking water: An analysis of drinking water sampled from three homes in Bradford County, Pa., revealed traces of a compound commonly found in Marcellus Shale drilling fluids, according to a study published on Monday. The study: Evaluating a groundwater supply contamination incident attributed to Marcellus Shale gas development.
      2. New study reveals potential Texas fracking contamination: A new peer-reviewed study reveals potential groundwater contamination in the Barnett Shale, a geological formation that underlies 17 counties in North Texas, including Denton County. But the cause is still under debate. The study: A comprehensive analysis of groundwater quality in the Barnett Shale region.
      3. Okla. science agency links quakes to oil: The state agency in charge of determining the cause of Oklahoma’s earthquake swarms announced today that it is “very likely” that the shaking has been caused by oil and gas activity. The statement: Statement on Oklahoma Seismicity.
    2. Health impacts
      1. Fracking produces air pollution that increases the risk of breathing problems and cancer, study claims: Researchers found that people living within three miles of a fracking site could be exposed to pollution levels that are significantly higher than the Environmental Protection Agency (EPA) deems safe. The study: Impact of natural gas extraction on PAH levels in ambient air.
      2. Lower birth weight associated with proximity of mother’s home to gas wells: Pregnant women living close to a high density of natural gas wells drilled with hydraulic fracturing were more likely to have babies with lower birth weights than women living farther from such wells, according to a University of Pittsburgh Graduate School of Public Health analysis of southwestern Pennsylvania birth records. The study: Perinatal outcomes and unconventional natural gas operations in southwest Pennsylvania.
    3. Policy
      1. Fracking poses ‘significant’ risk to humans, says new EU report: A major new scientific study has concluded that the controversial gas extraction technique known as fracking poses a “significant” risk to human health and British wildlife, and that an EU-wide moratorium should be implemented. The report: Chemical Pollution from Fracking.
      2. New York makes fracking ban official: The Commissioner of the Department of Environmental Conservation announced the decision on Monday, saying a ban was the only reasonable alternative after years of exhaustive research and examination of the science and facts.
  5. DDT in pregnancy may raise breast cancer rates in daughters
    The researchers observed a sizable, statistically significant association between in utero DDT exposure and risk of breast cancer in young women and a possible association with more aggressive tumors. These findings are the first ever reported for a prospective observation of a large pregnancy cohort. The study: DDT exposure in utero and breast cancer.
  6. US government recommends lower level of fluoride in water
    For the first time in more than 50 years, the federal government has recommended lowering the level of fluoride in drinking water. The recommendation: U.S. Public Health Service Recommendation for Fluoride Concentration in Drinking Water for the Prevention of Dental Caries.
  7. Antibiotic use reduction
    After decades of warnings, the issue of antibiotic overuse and resistance is gaining traction.

    1. White House opens ‘superbug’ summit, orders federal cafeterias to use meat raised with ‘responsible antibiotic use’: President Obama kicked off the day-long, mostly-closed-door meeting by directing federal departments and agencies to begin a process to buy meat and poultry raised with “responsible antibiotic use.”
    2. What Tyson’s pledge to stop using human antibiotics in chicken means for the future of superbugs: The Natural Resources Defense Council called the Tyson news a “tipping point for getting the chicken industry off antibiotics.” Yet when it comes to protecting against antibiotic resistance, critics say the change may be too little and too late.
  8. US chemical regulation reform gets boost as House passes TSCA rewrite
    The US House of Representatives overwhelmingly approved a bipartisan bill that would update the nation’s industrial chemicals regulations for the first time in nearly 40-years. The bill—which would make it easier for the Environmental Protection Agency (EPA) to request new safety data on chemicals and regulate chemicals already on the market—takes a narrower approach than a competing bill in the Senate. See analyses of the bill: Who is looking out for the health of America’s children? House chemicals bill favors industry over families and The House passes TSCA reform!
  9. Parma consensus statement on metabolic disruptors
    A multidisciplinary group of experts gathered in Parma, Italy, for a workshop hosted by the University of Parma, May 16-18, 2014, to address concerns about the potential relationship between environmental metabolic disrupting chemicals, obesity and related metabolic disorders.
  10. Improving population-wide nutrition
    US agencies announced nutrition recommendations and a new ban.

    1. Scientific Report of the 2015 Dietary Guidelines Advisory Committee
      The overall body of evidence examined by the 2015 DGAC identifies that a healthy dietary pattern is higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and drinks and refined grains.
    2. FDA cuts trans fat in processed foods: The US Food and Drug Administration is taking a step to remove artificial trans fat from the food supply within three years. This step is expected to reduce coronary heart disease and prevent thousands of fatal heart attacks every year.

State of the Evidence: What Is the Connection between Chemicals & Breast Cancer?

The Breast Cancer Fund and Breast Cancer Action
edited by Nancy Evans

EXECUTIVE SUMMARY
Breast cancer rates have been climbing steadily in the United States and other industrialized countries since the 1940s. Billions of dollars have been spent in an effort to stem this unrelenting tide, yet more than 50 percent of breast cancer cases remain unexplained by the characteristics and risk factors associated with the disease.

Ionizing radiation is the only proven environmental cause of human breast cancer. But powerful circumstantial evidence indicates that some of the 85,000 synthetic chemicals in use today are responsible for many of the unexplained cases of the disease. While scientists have not yet developed an ideal method for linking chemical exposures to breast cancer, several types of research – experimental, body burden and ecological studies – provide strong evidence of the connection between chemicals and breast cancer.

Because the types of evidence vary, the strength of the evidence linking chemicals and breast cancer also varies. The strongest evidence linking chemicals to breast cancer – based on the fact that lifetime exposure to natural estrogens increases the risk of breast cancer – concerns natural and synthetic estrogens, including drugs like diethylstilbestrol (DES), plastic additives like bisphenol-A (BPA), polyvinyl chloride (PVC) (found in many consumer products), dieldrin and some pesticides. Other synthetic substances strongly linked to breast cancer through experimental evidence are organic solvents (used in many manufacturing processes, including the manufacture of computer components), polycyclic aromatic hydrocarbons (PAHs) (created in soot and fumes from burning diesel, fuels or cigarettes) and 1,3 butadiene (a by-product of internal combustion engines).

There are also chemicals for which the evidence indicates a probable but less certain link to breast cancer. These chemicals include dioxin (created when plastics or other materials containing chlorine are burned), the pesticide DDT (dichloro-diphenyl-trichloroethane) and its metabolite DDE, and PCBs (polychlorinated biphenyls), previously used in the manufacture of electrical equipment and other industrial and consumer products.

Finally, there is evidence of chemicals that affect how the body functions in ways that suggest a possible link between these substances and breast cancer. These chemicals include the insecticide heptachlor and phthalates, used to make plastic soft and flexible.

We clearly have major gaps in our current knowledge about the links between breast cancer and the environment. Therefore, we need to focus our research efforts in areas that are most likely to provide useful information for framing public policies related to chemical exposures and our health. The types of research most likely to produce useful evidence will be those examining (1) workplace exposures, (2) household exposures and (3) breast milk as a marker for human contamination.

While we pursue the research that will lead to more definitive answers, the existing evidence linking chemicals to breast cancer demands that we act now as a society to begin removing many of these substances from our environment. Considerable resources are spent encouraging women to make changes in their personal lives in an effort to reduce their risk of breast cancer. But breast cancer is not just a personal tragedy; it is a public health crisis that demands action by society as a whole.

This crisis must be addressed by beginning now to implement the precautionary principle. Under this principle, evidence of harm, rather than definitive proof of harm, is the trigger for policy action. In addition, the precautionary principle mandates that the burden of proof with regard to chemicals rests with the manufacturers to demonstrate that the substances are safe, rather than with the public to show that they are harmful. Finally, the precautionary principle rests on the democratic principle that government officials are obligated to serve the public’s interest in human health and environmental protection.

The following 5-point plan will help us reduce the risk of breast cancer and ultimately end the epidemic:

  1. PHASE OUT TOXIC CHEMICALS that are omnipresent in the lives of so many people.
  2. ENACT “SUNSHINE” LAWS AND ENFORCE EXISTING ENVIRONMENTAL PROTECTION LAWS to reduce the use of toxics by requiring companies to report how many tons of chemicals they use.
  3. PRACTICE HEALTHY PURCHASING, with local, state and federal governments leading the way in purchasing environmentally preferable products, thereby creating an example for individuals to follow.
  4. OFFER CORPORATE INCENTIVES that encourage businesses to eliminate the use of harmful chemicals in their products and processes.
  5. MONITOR BREAST MILK through a comprehensive community program that identifies the chemicals present in breast milk, establishes links to geographic areas and initiates a plan to eliminate these contaminants.

We ignore at our peril the increasing evidence that chemicals are contributing to the rising tide of breast cancer. The obligation to understand this evidence, and begin to address it through the implementation of public policies that put health first, rests with all of us. It is in our power to change the course we are on. Now is the time.

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