Estrogen Alone Apparently Okay

A useful summary from The Scientist online.

Exogenous estrogen by itself does not raise the risk of breast cancer among women who have had a hysterectomy, and appears to even reduce the risk of some types of the disease, according to findings from the Women’s Health Initiative released in the Journal of the American Medical Association (JAMA) this week. The authors suggest that progestin — a synthetic progesterone already blamed for a number of diseases — may be the culprit in the increase in cancer rates following hormone replacement therapy (HRT) that combines estrogen and progestin.