Posted on October, 18 2006

The realisation that natural hormones play a role in breast cancer has led to renewed concerns about chemicals with hormonal activities found in food, personal care products or as environmental contaminants. It is still not possible to be certain that hormone or endocrine disrupting chemicals play a role in breast cancer, but two findings have emerged from recent scientific research that increase the biological plausibility that this might be the case. These are (a) the importance of the combined action of several chemicals – the “cocktail effect” – and (b) the existence of critical periods early in life and during development in the womb that make women particularly sensitive to breast cancer-causing factors.

In the light of this new evidence, the role of chemicals in breast cancer requires urgent attention, and precautionary action is warranted to reduce exposure. This briefing explains the role of oestrogens in breast development, and the evidence for suggesting that man-made chemicals may be implicated in the increased incidence of breast cancer.