UCLA researchers say post-menopausal women who develop breast tenderness after undergoing combination hormone therapy are at higher risk for breast cancer than women who take estrogen alone.

In general, women taking estrogen and progestin were more likely to develop breast tenderness than women who took only estrogen, study author Dr. Carolyn Crandall said.

Crandall said post-menopausal women on combination therapy probably developed breast tenderness they didn't have before because their breasts became more dense. For women who took only estrogen, the study showed that even if they developed breast tenderness, their breasts did not become more dense.

 Crandall said the study is important because it shows that combination hormone therapy may protect a woman from uterine cancer but increase her risk of breast cancer.

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