Breast tenderness during hormone replacement therapy linked to elevated cancer risk

Women who developed new-onset breast tenderness after starting estrogen plus progestin hormone replacement therapy were at significantly higher risk for developing breast cancer than women on the combination therapy who didn't experience such tenderness, according to a new UCLA study. The research, published in the Oct. 12 issue of the Archives of Internal Medicine, is based on data from more than 16,000 participants in the Women's Health Initiative estrogen-plus- progestin clinical trial. This trial was abruptly halted in July 2002 when researchers found that healthy menopausal women on the combination therapy had an elevated risk for invasive breast cancer. Researchers do not know why breast tenderness indicates increased cancer risk among women on the combination therapy, said the new study's lead researcher, Dr. Carolyn J. Crandall, a clinical professor of general internal medicine and health services research at the David Geffen School of Medicine at UCLA. "Is it because the hormone therapy is causing breast-tissue cells to multiply more rapidly, which causes breast tenderness and at the same time indicates increased cancer risk? We need to figure out what makes certain women more susceptible to developing breast tenderness during hormone therapy than other women," Crandall said. Of the participants in the trial, 8,506 took estrogen plus progestin and 8,102 were given placebos.