Report Details New Links Between Environmental Toxicants and Breast Cancer

SAN FRANCISCO – A new report on environmental links to breast cancer concludes that exposure to synthetic chemicals and radiation has contributed more than previously thought to the rising incidence of breast cancer.

The report, “State of the Evidence 2004: What Is the Connection Between the Environment and Breast Cancer?” was jointly released today by the Breast Cancer Fund, a non-profit environmental health organization, and Breast Cancer Action, a non-profit national education and advocacy organization. It also offers policy recommendations to help reduce the risk of breast cancer.

According to the report, fewer than one in 10 cases of breast cancer occurs in women born with a genetic predisposition for the disease. As many as 50 percent of breast cancer cases remain unexplained by personal characteristics and other traditionally-accepted risk factors; epidemiologists and other scientists increasingly believe many cases are linked to environmental factors.

This third edition of the report amasses new evidence from 21 research studies published since February 2003, adding to existing evidence linking toxicants in the environment to breast cancer. This year, 40,000 women in the United States will die from breast cancer-one death every 13 minutes. The new report was peer-reviewed by six leading scientists, including a noted scientist from the International Agency for Research on Cancer, a division of the World Health Organization.

Among the new research findings reported:

  • Chlorinated chemicals, found in drinking water and many industrial processes such as computer component manufacturing, were associated with an elevated risk of breast cancer in three new studies;
  • A solvent used in many varnishes, paints, dyes and fuel additives (ethylene glycol methyl ether) was found to sensitize breast tissue cells to the effects of estrogens and progestins, thereby increasing the risk of breast cancer and;
  • The Million Women Study in the United Kingdom revealed that all types of postmenopausal hormone replacement therapy significantly increased the risk of breast cancer, underscoring earlier findings from the Women’s Health Initiative study in the United States. Another study found that use of HRT after previously being diagnosed with breast cancer tripled a woman’s risk of recurrence or development of a new breast tumor.

“Far too many chemicals are unleashed on our environment without first being tested for long-term effects,” said Jeanne Rizzo, executive director of the Breast Cancer Fund. “We call on both government and industry to rethink the process by which new chemicals are authorized for use.”

Barbara Brenner, executive director of Breast Cancer Action, said, “We need to take action to promote public policy that will reduce and eventually eliminate our exposures to toxic chemicals in the air we breathe, the water we drink and the food we eat.”

In the past fifty years, a woman’s lifetime risk of breast cancer more than tripled in the United States, to one in seven today. This trend parallels a staggering increase of chemicals in the environment: the report says that “compelling scientific evidence” points to some of the 85,000 synthetic chemicals in use today as contributing to breast cancer by altering hormone function or gene expression.

“This new report offers the clearest evidence yet that the rise in breast cancer incidence is linked to exposure to radiation and toxic chemicals,” said Nancy Evans, a health science consultant for the Breast Cancer Fund and the editor of the report. “Medical X-rays, pesticides, household cleaning products, personal care products and some pharmaceuticals-these are just a few of the multiple and chronic exposures contributing to this epidemic.”

The report details how exposure to certain common chemicals known to increase the risk of breast cancer occurs often in the home and the workplace. These chemicals, known as xenoestrogens because they mimic or act like estrogens in the body, include: Bisphenol-A, used in plastic food containers and baby bottles; polyvinyl chloride (PVC), used extensively in food packaging, as well as in medical products, appliances, cars, toys, credit cards and rainwear; pesticides used on lawns and in commercial agriculture; and diethylstilbestrol, a drug prescribed for millions of pregnant women from 1941 to 1971 that doubled the risk of breast cancer for women who were exposed to it in the womb and who are now over 40.

A 2003 U.S. study by the Centers for Disease Control revealed the presence of 116 chemicals-some of them banned for more than two decades because of toxicity-in people of all ages.

In addition, the report also highlights the effects of exposure to ionizing radiation, the best-established cause of breast cancer. Paralleling the dramatic increase in exposures to toxic chemicals, an increase in radiation exposure from X-rays, CT scans, fluoroscopy, nuclear fallout and other sources may have contributed to a rising incidence of breast cancer between 1950 and 1991, the report says. During the same period, the incidence of breast cancer in the United States increased by 90 percent.

The new report offers a “Six-point Plan to Help Reduce the Risk of Breast Cancer and Ultimately End the Epidemic.” Among those recommendations:

  • Phase out chemicals known to cause cancer or genetic harm and test all others to determine the effects on human health and the environment;
  • Hold corporations accountable for hazardous practices and offer incentives for clean, green practices;
  • Educate the public about the health effects of radiation and on how to reduce their exposure and;
  • Establish a comprehensive biomonitoring program to measure the presence of chemicals in people and track resultant health outcomes.