Bisphenol A in polycarbonate plastics (baby-bottles, cups, microwave bowls etc) may cancel the benefit of some anti-cancer treatments. When I was writing Anticancer: A New Way of Life, we already knew that when certain plastics based on PVC (polyvinyl chloride) are exposed to warm liquids, they may diffuse toxic substances in the body, whose action on hormonal receptors may stimulate the growth of some cancers (particularly breast cancers, but in some cases also prostate cancer and cancers of the brain). Now a new study has specifically implicated Bisphenol A – one of the components of the PVC present in polycarbonate plastics – in stimulating resistance to cancer treatments. Hardened polycarbonate plastics are used to make numerous types of containers that we use every day: electric kettles, disposable glasses and cups, baby-bottles, tins, soda cans, and even some dental crowns. When exposed to warm liquids they diffuse BPA (Bisphenol A), which has long been suspected to contribute to the progression of some cancers, and which was recently implicated by the US National Toxicology Program and by the Canadian government agency Health Canada. In a new study, researchers from the University of Cincinnati observed that even at very low concentrations, BPA blocks the effects of several chemotherapy agents on various lines of breast-cancer cells. The concentrations that they observed were comparable to those resulting from exposure to warm liquids that have been in contact with containers made of polycarbonate plastics. These results are extremely important, because the three chemotherapy drugs under study (doxorubicin, cisplatin and vinblastine) use very different mechanisms to stop the growth of cancerous cells. In addition, the study found that BPA protected both estrogen-receptor positive and negative breast cancer tumors. This means that BPA protects cancer cells at the deepest level of their capacity for survival – not just through hormonal effects, or via a single mechanism which might impact only a few chemotherapy drugs. By extension, therefore, it’s possible that BPA protects every kind of cancer from every kind of treatment.

My recommendation: It seems to me essential that we apply the precaution principle in our own lives. In the absence of additional data, if you suffer from cancer, and if you are undergoing treatment (whether using chemotherapy, radiotherapy or other therapies), be especially careful NOT to expose yourself to warm liquids that have been in contact with plastic containers. Note that the problem does not occur with plastics that have not been heated, for example bottled water, or plastic containers in the fridge or freezer.

1. LaPensee EW, Tuttle TR, Fox SR, Ben-Jonathan N. Bisphenol A at Low Nanomolar Doses Confers Chemoresistance in Estrogen Receptor Alpha Positive and Negative Breast Cancer Cells. Environ Health Perspect 2008:doi: 10.1289/ehp.11788 (available at