Traces of Banned Toxins DDT, PCB Not Linked to Breast Cancer, Study Finds

A new study offers the strongest evidence yet that lingering traces of the banned chemicals DDT and PCBs do not trigger breast cancer, as some have feared. DDT and PCBs often are cited by those who argue that toxins in the environment are responsible for the steady increase in breast cancer over the past half-century. The chemicals are thought to mimic the harmful effects of the female hormone estrogen.

The research, part of the long-running Nurses Health Study, examined blood samples donated in 1989 and 1990 by 240 women who were later diagnosed with breast cancer. The study, reported today in the New England Journal of Medicine, found that levels of DDT metabolites or PCBs in the women with breast cancer were no higher than those in healthy women.