Postmenopausal hormone therapy and breast cancer.

(1) According to the WHI trial, postmenopausal hormone replacement therapy exposes women to an additional risk of breast cancer of about 8 cases a year per 10 000 treated women; (2) In the United States, a comparison of the breast cancer incidence rates in 2001 and 2004 showed an overall annual decrease of 8.6%, attributable to the reduction in the use of hormone replacement therapy in postmenopausal women. A similar phenomenon was observed in France, Germany and Canada; (3) In summary, if prescribers had waited for the results of the WHI trial, many cases of breast cancer would probably have been avoided.