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Study: Hormone therapy increases breast cancer risk

Category: Breast

Women who develop new-onset breast tenderness after beginning estrogen plus progestin hormone replacement therapy are at a higher risk for acquiring breast cancer, according to new research.

The study, published in the October 12 issue of the Archives of Internal Medicine, examined breast tenderness and the occurrence of cancer in more than 16,000 patients in the Women's Health Initiative estrogen-plus-progestin clinical trial.

Compared with a placebo-controlled group, women on the hormone therapy who did not have breast tenderness at the beginning of the trial were three times more likely to develop tenderness after one year, according to mammography lab tests. Furthermore, this group experienced a 48 percent higher risk of invasive breast cancer than those on the combination therapy who did not report tenderness after one year.

Dr Carolyn J. Crandall, the UCLA study's lead researcher, hypothesized that "Hormone therapy is causing breast-tissue cells to multiply more rapidly, which causes breast tenderness," leading to a greater risk of developing cancer.

Researchers quickly stopped the trial in 2002 after discovering that the combination therapy led to an elevated cancer risk in healthy menopausal women.
The Centers for Disease Control and Prevention reports that in 2005, a total of 41,116 women and 375 men died from breast cancer.