Breast Cancer and the Environment

Despite our decades-old war on cancer, women today are much more likely to develop breast cancer than any previous generation.

Many of the established risk factors for breast cancer—such as earlier menarche, later menopause, childlessness, and delayed childbearing—are ones women cannot change. And established risk factors do not account for all breast cancer cases. We simply do not know as much as we should.

Many people are now looking at our increasingly polluted environment as a possible culprit. Breast cancer incidence in the United States has risen since World War II, when industry began pumping out pesticides, plastics, solvents, and other chemicals, leaving residues in our air, water, and soil. Laboratory studies suggest that many of these chemicals may cause breast tumors, hasten their growth, or leave mammary glands more vulnerable to carcinogens.

The United States saw a decline in breast cancer incidence in 2003 and 2004, a change that has been largely attributed to post-menopausal women discontinuing their hormone replacement therapy after research showed that it can cause breast cancer. This trend actually strengthens the hypothesis that other exogenous hormones and hormone mimics increase the risk of breast cancer.

Despite these gathering clues, though, few studies have investigated the effects of modern chemicals on women’s breast health. If we are to have genuine hope of defeating the breast cancer epidemic, we must find ways to prevent the disease from even developing. And we must view environmental toxics as possible targets for our prevention efforts.