[Causal interactions of estrogens and alcohol in cancer of the breast]

The majority of studies and meta-analyses tend to show a very slight increase of risk of beast cancer in post-menopausal women receiving hormone replacement therapy (HRT). Such results must however be interpreted in light of biases including intensive follow-up in women taking HRT and unknown or new parameters.

Several publications have demonstrated an increased relative risk of breast cancer in women consuming alcohol. This increase rises linearly with the level of alcohol intake. To date, this parameter has been neglected in post-menopausal women taking HRT. Two studies have demonstrated a rise in breast cancer in women taking HRT who drink alcohol. No particular explanation is put forward.

Based on an experimental human study, E. Ginsburg has shown that there is a considerable and long-duration increase in estradiolemia in women on HRT who also drink alcohol. This hyperestradiolemia could exceed the promotion threshold of breast carcinogenesis. This new parameter must be taken into consideration as effective preventive measures can be implemented: convincing women taking HRT to limit their alcohol intake.