Is the recent fall in incidence of post-menopausal breast cancer in UK related to changes in use of hormone replacement therapy?

There has been a substantial decline in the use of female sex hormone replacement therapy (HRT) in the United Kingdom, particularly by post-menopausal women, since around 2000–2001. Given what is known of the risk of breast cancer in women receiving HRT, the decline in use should have resulted in a decrease in risk, and incidence rates about 14% lower than expected were predicted for the age group 50–59 in 2005.There has been a recent slowing and reversal of the increasing trends in incidence of breast cancer in the age group 45–64. This is most marked at ages 50–59, where rates since 1999 have been decreasing at 0.8% a year, following a long period of sustained increase.It seems probable that these two events are causally related.