Study Lists Environmental Factors Linked to Breast Cancer

Susan G. Komen for the Cure and the Silent Spring Institute have announced the publication of "Environmental Factors in Breast Cancer," the most comprehensive review to date of scientific research on environmental factors that may increase breast cancer risk. According to the findings, women face daily and widespread exposure to hundreds of chemicals linked to breast cancer.

The study's findings were released on May 14 in the online version of the scientific journal Cancer. A hard copy version of the study will appear as a supplement to the June 15 issue of Cancer.

The state-of-the-science review, commissioned by Komen for the Cure and conducted by the Silent Spring Institute with additional researchers from Harvard University, Roswell Park Cancer Institute and the University of Southern California, collected and assessed existing scientific reports on potential links between specific environmental factors and breast cancer.

The researchers synthesized national and international data sources and identified 216 chemicals that cause breast tumors in animals. They used the information to create a unique searchable online database featuring detailed information on the carcinogens.

The database, accessible at, is available free of charge and will be of particular interest to researchers, healthcare workers, policymakers and some members of the public.

Komen for the Cure's goal in funding Silent Spring initiative was to determine where there is consensus within the scientific community on the relationship between environmental factors and breast cancer and where additional research or improved research methods are needed. Such information can help guide public policy and help funding organizations like Komen for the Cure to determine where to most effectively target research grant funds.

The database includes references to 900 studies, 460 of which are human breast cancer studies that were critically evaluated by the research team. The studies measure breast cancer risk related to body size, physical activity, environmental pollutants and prospective studies of diet. For each study, bibliographic information, key methods and findings, and a critical assessment of the strength of the evidence is included.

The database reveals that among the 216 compounds that cause breast tumors in animals:

  • 73 have been present in consumer products or as contaminants in food.
  • 35 are air pollutants.
  • 25 have been associated with occupational exposures affecting more than 5,000 women a year.
  • 29 are produced in the United States in large amounts, often exceeding 1 million pounds per year.

"Komen is eager to see quality science yield answers that will eventually lead us to our ultimate goal of knowing how to prevent breast cancer. Commissioning this study is a step toward that goal, because it helps to determine what is known and what is not known about the possible link between certain environmental factors and the incidence of breast cancer," said Hala Moddelmog, president and CEO of Komen for the Cure.

"While it is disturbing to learn that there are so many chemicals that may be linked to breast cancer, there also is a great opportunity to save thousands of lives by identifying those links, limiting exposure and finding safer alternatives. It is critical that we integrate this information into policies that govern chemical exposures," said Julia G. Brody, PhD, executive director of the Silent Spring Institute.

The Silent Spring Institute study also examined lifestyle influences on breast cancer, such as physical activity and diet. The study results underscore the importance of regular, life-long physical activity to lower a woman's risk of developing breast cancer. The study concluded that further research is needed to determine the relationship between dietary factors and breast cancer risk.

In response to the study's findings, Komen is now funding the development of new and innovative models for researching breast cancer and environmental risk factors. Komen also continues to fund environmental projects as part of its investigator-initiated grants program and is actively looking for ways to partner with other research groups such as the U.S. Centers for Disease Control and Prevention Environmental Health Labs.

This article originally appeared in the 05/01/2007 issue of Environmental Protection.

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