Statin use and breast cancer: do we need more evidence and what should this be?

3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) have been proved highly effective treatments for primary and secondary prevention of cardiovascular diseases. Despite widespread and long-term use of statins, there is still a debate concerning their association with cancer at various sites, including breast. As of today, the accumulated epidemiological evidence does not support the hypothesis that statin use affects the risk of developing breast cancer when taken at low doses for managing hypercholesterolemia. However, current evidence cannot exclude an increased risk of breast cancer with statin use in subsets of individuals, for example, the elderly. On the other hand, some studies show that statins might be useful to prevent recurrence and improve survival in patients already suffering from certain breast cancer types. They could also be combined with certain anticancer drugs and potentiate their effects, ameliorate their side effects or prevent the development of resistance. Further research is warranted to clarify these issues.