Is the decrease in breast cancer incidence related to a decrease in postmenopausal hormone therapy?

Following the Women's Health Initiative (WHI) publication in mid 2002, a drastic decrease in hormone therapy for postmenopausal women has been observed worldwide. Since 2007, the reported incidence in breast cancer has declined. Most authors have linked this decline to the reduction in hormone treatment. In this paper we discuss why these ecological observations are not fully convincing and focus on the importance of screening and variations in other risk factors to interpret this decline in breast cancer.