Breast Cancer Incidence Stayed Low After HRT Decline

HOUSTON, April 18 -- Evidence linking a decrease in the annual incidence of breast cancer to a decline in hormone replacement therapy is as robust as first reported, investigators here said. As Peter Ravdin, M.D., Ph.D., of the University of Texas M.D. Anderson Cancer Center, and colleagues reported at the San Antonio Breast Cancer Symposium last December, the incidence fell 7% from 2002 to 2003, reversing a 20-year trend.
That reversal followed closely on the heels of publication of the Women's Health Initiative results, which showed that five years of hormone replacement therapy (HRT) in postmenopausal women increased breast cancer risk by 24%, and a subsequent plunge in HRT prescriptions.
And now, in an extended analysis of their previous study, Dr. Ravdin, and colleagues, showed that the breast cancer incidence was unchanged from 2003 to 2004, indicating that the decline they had previously seen was not a statistical fluke, they reported in the April 19 issue of the New England Journal of Medicine.
"This kind of study can't prove causality, but the data present a very compelling link between hormone replacement therapy and breast cancer," said co-author Donald Berry, Ph.D., also of M.D. Anderson.
In their earlier report, Dr. Ravdin and colleagues used data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, which collects information on 9% of the U.S. population, to study breast cancer rates.
Using the SEER data, they found that the total decrease from 2002