Trial Information

A Population-Based Randomized Trial to Assess the Effects of Short-Term Cessation of Hormone Replacement Therapy (HRT) on Mammography Assessments and Breast Density

This randomized, controlled trial is designed to test whether short-term (1-2 months) HRT
cessation will sufficiently lower breast density to decrease the proportion of women who
receive a recommendation for additional evaluation following a screening mammogram, and to
examine whether there is a trend by duration of cessation. The study is being conducted at
Group Health Cooperative, a managed health care organization in western Washington State
with an organized breast cancer screening program. We are recruiting 1,500 women and will
randomize women to one of three HRT arms: 1) cessation two months before the screening
mammogram; 2) cessation one month before; and 3) continued HRT use. We are using a
computer-assisted method to measure mammographic breast density continuously. Mammography
recall rates are being determined from an expert radiologist review of the mammograms,
blinded to HRT status.