Does hormone replacement therapy increase the risk of breast cancer?

The data contained in the literature about breast cancer risk and hormone replacement therapy is reviewed. Many studies with different methodologies have been published. Analysis of classical papers or of meta-analysis do not support the view that short-term use of hormone replacement therapy significantly increases the risk of breast cancer. In some clinical situations such as family history of breast cancer, high dose estrogens and especially in the case of long term treatment over 10 years, risk of cancer could be increased and requires a specific clinical management. Despite of the absence of double blind placebo-controlled trial, there is no strong data available to oppose the use of estrogen replacement therapy because of an hypothetic increased risk of breast cancer. Using a low posology for less than 5 years in correctly managed women is a safe attitude.