Common chemicals linked to breast cancer

Writing in a publication of the American Cancer Society, researchers concluded that reducing exposure to the compounds could prevent many women from developing the disease.

The research team from five institutions analyzed a growing body of evidence linking environmental contaminants to breast cancer, the leading killer of U.S. women in their late 30s to early 50s.

Experts say that family history and genes are responsible for a small percentage of breast cancer cases but that environmental or lifestyle factors such as diet are probably involved in the vast majority.

"Overall, exposure to mammary gland carcinogens is widespread," the researchers wrote in a special supplement to the journal Cancer. "These compounds are widely detected in human tissues and in environments, such as homes, where women spend time."

The scientists said data were too incomplete to estimate how many breast cancer cases might be linked to chemical exposures.

But because the disease is so common and the chemicals so widespread, "the public health impacts of reducing exposures would be profound even if the true relative risks are modest," they wrote. "If even a small percentage is due to preventable environmental factors, modifying these factors would spare thousands of women."

The three reports and a commentary were compiled by researchers from the Silent Spring Institute, a women's environmental health organization in Newton, Mass.; Harvard's Medical School and School of Public Health in Boston; the Roswell Park Cancer Institute in Buffalo, N.Y.; and USC's Keck School of Medicine. Silent Spring Institute Executive Director Julia Brody led the team.

In response to the findings, Susan G. Komen for the Cure, a breast cancer prevention group that funded the work, pledged an additional $5 million for developing research tools to root out environmental causes.

Reviewing hundreds of existing studies and databases, the team produced what it called "the most comprehensive compilation to date of chemicals identified as mammary carcinogens." No new chemical testing was conducted for the reports.