Statins and breast cancer: a smoking gun or guilt by association?

Statins are widely prescribed, effective cholesterol-lowering drugs. Indeed, atorvastatin and simvastatin were the most commonly prescribed drugs in the US in 2004, with > 70 million prescriptions written for atorvastatin alone. Statins are pleiotropic agents and, after an early study of patients with coronary heart disease showed a lower than expected incidence of cancers, preclinical studies were carried out that have supported the potential anticancer activity of these compounds. However, clinical reports on the relationship between statin use and breast cancer risk have yielded mixed results, with no association and both positive and negative associations being observed. Because breast cancer is the most frequent cancer in women, any link between statin use and breast cancer risk would have major public health implications. The current evidence suggests that statins are safe and effective agents in treating hyperlipidaemia and no evidence of increase or decrease risk of breast cancer. Indeed, more research is needed to define whether long-term statin therapy may decrease or increase the risk of breast cancer.