Environment and Breast Cancer: Science Review

Families and friends of women touched by breast cancer are calling for increased attention to research into the environmental causes - any factors that are not hereditary. The goal is to find causes of breast cancer that can be reduced or eliminated to prevent the disease.

To build an evidence-based strategy for preventing breast cancer, Susan G. Komen for the Cure invited Silent Spring Institute and their partners at Harvard University, Roswell Park Cancer Institute, and the University of Southern California to assess the scientific evidence on environmental causes. In the first year, the team reviewed areas of emerging research that promise to reveal new opportunities for risk reduction:

environmental pollutants
dietary factors
body size and shape
physical activity
interactions of these factors with inherited genes

What is Cancer?

Cancer is the uncontrolled spread and growth of abnormal cells.

Some people are born with abnormal cells. Sometimes, changes in cells happen later. Cancer can start anywhere in the body and is affected by a variety of things that go on for a long time both inside and outside our bodies.

The cornerstone of the LIBCSP is the Breast Cancer and the Environment on Long Island Study, which was undertaken to determine whether certain environmental contaminants increase risk of breast cancer among women on Long Island. This investigation has been led by Dr. Marilie Gammon, of the University of North Carolina (UNC) at Chapel Hill, and has been a collaborative effort of New York City and Long Island researchers.

The primary aims were to determine if organochlorine pesticides, including DDT, polychlorinated biphenyls (PCBs), dieldrin, and chlordane, and polycyclic aromatic hydrocarbons (PAH), a ubiquitous pollutant caused by incomplete combustion of various chemicals including diesel fuel and cigarette smoke, are associated with risk for breast cancer among women on Long Island.

Dr. Gammon and colleagues reported the major findings from the study in August 2002. They found that organochlorine compounds are not associated with the elevated rates of breast cancer on Long Island. However, the researchers said that it is possible that breast cancer risk in some individuals may be associated with organochlorine exposures because of individual differences in metabolism and ability to repair DNA damage, and they are continuing to investigate these possibilities. The researchers also found that exposure to PAHs was associated with a modest increased risk for breast cancer.

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Marilie D. Gammon, Ph.D., principal investigator
Universtiy of North Carolina at Chapel HillChapel Hill, N.C.