Cancer

A critical assessment of epidemiologic research on breast cancer and environmental pollutants, diet, physical activity, and body size is provided and toxicologic research on animal mammary gland carcinogens reveals opportunities for risk reduction and future research needs. The risk of breast cancer for women in mid-life makes prevention-oriented research a public health priority.

Chemicals that increase mammary gland tumors in animals may also be breast carcinogens in humans. The current study reports on 216 mammary gland carcinogens that include industrial chemicals, chlorinated solvents, products of combustion, pesticides, dyes, radiation, drinking water disinfection byproducts, pharmaceuticals and hormones, natural products, and research chemicals.

Targets for breast cancer research include numerous environmental pollutants that cause mammary gland tumors, disrupt hormones, or affect mammary gland development and susceptibility in laboratory studies. Although to the authors' knowledge most have never been included in human breast cancer research, critical reviews of epidemiologic studies have shown some evidence of an association with polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and, to a lesser extent, organic solvents.

Prospective studies are reviewed and summarized on selected dietary factors, gene-diet interactions, and breast cancer incidence. Among the prospective epidemiologic studies conducted on diet and breast cancer incidence and gene-diet interactions and breast cancer incidence, to date there is no association that is consistent, strong, and statistically significant, except for alcohol consumption, overweight, and weight gain.