US breast cancer fall: better drugs or less HRT?

A debate has arisen in the USA, following the announcement at the annual San Antonio Breast Cancer Symposium of figures which show a 7% drop, over a one year period to 2003, in the number of reported breast cancer cases. The fall represents approximately 14,000 fewer women developing breast cancer.

Donald Berry, a biostatistician at the University of Texas' MD Anderson Cancer Center in Houston, presented the data, which also showed a fall of one fifth for postmenopausal women whose cancers were linked to estrogen levels. The findings reinforce the view that hormone replacement therapy may be linked to some breast cancer cases. In July 2002, a Women's Health Initiative study of over 16,000 women aged 50 to 79 who were using a combination of estrogen and progestin had "a significant risk of breast cancer." According to news reports, the use of HRT fell between 30%-50% in the six months following the WHI report.

However, figures for the years leading up to the HRT study show that there was a smaller decline, about 1% per year, in breast cancer cases. A campaign against mammographies, claiming that they are harmful, was also cited as possibly affecting the reporting of breast cancer, because 3% fewer women are recorded as having been tested in 2002.