May 14, 2007 Update: Cancer publishes Silent Spring Institute's review of environmental factors and breast cancer

Breast cancer incidence rates continue to rise worldwide, with the highest risk in industrialized western countries. Immigrants from low risk regions, such as Asia, to a high-risk region, such as the US, face increased risk. These and other data tell us that characteristics of modern societies affect risk. Known breast cancer risk factors -- such as number of pregnancies, age at first full-term pregnancy, and HRT use -- contribute to, but do not adequately account for, variations in risk. Identifying additional non-inherited factors is critical, because it will tell us ways to reduce risk.

A team of researchers from Silent Spring Institute, Harvard University, Roswell Park Cancer Institute, and University of Southern California conducted a review of scientific literature on possible environmental factors in breast cancer. The team focused on diet, physical activity, body size, environmental pollutants, gene-environment interactions, and early life exposures. Some of these exposures may affect breast cancer risk through hormonal mechanisms similar to those identified for the established breast cancer risk factors. For example, endocrine disrupting compounds (chemicals that mimic or disrupt hormones) are hypothesized to affect risk, because estrogen and other hormones are known risk factors; and estrogen mimics in common products, such as detergents and cosmetics, make breast cancer cells grow in laboratory studies. Exposures to chemicals that cause mammary tumors in animals, may initiate tumors by damaging DNA. In addition, researchers are increasingly focusing on possible developmental effects -- effects of exposures at critical periods, particularly prenatally and during adolescence. Silent Spring Institute researchers custom-designed a bibliographic database that is a repository for assessments of the scientific literature to date. The systematic review, published in Cancer on May 14, 2007, identifies strengths and gaps in the evidence, opportunities for risk reduction, and recommendations for the most promising areas for future research. This project is supported by the Susan G. Komen for the Cure.

Click here to link to this study's publications and online database