Estrogen Alone Has Little Benefit, Some Harm
No Effect on Breast Cancer, Heart Disease, but Increases Stroke Risk
WHI Results Reassuring
It's no big surprise that estrogen-only treatment slightly increases a woman's risk of stroke. The same risk was seen in the estrogen plus progestin arm of the study. What's reassuring is that estrogen-only treatment does not increase a woman's breast cancer or heart risk.
"It is good news that estrogen didn't increase women's risks of heart disease and breast cancer," Rebar says. "The risk of stroke is known, and modest. As with any medicine, a patient must weigh the risks. For symptomatic women, estrogen remains a viable choice."
Young Women Different
Women younger than 50 who have early menopause -- due to premature ovarian failure or having their ovaries removed -- tend to suffer severe menopausal symptoms. Such women often receive estrogen therapy. Alving says the WHI results don't apply to these women.
The ASRM's Rebar agrees that younger women are a separate group of patients.
"The data from WHI may not be applicable to a group of women who are different from those included in the trials," Rebar says. "Younger women with ovarian failure may well be a separate category. I have told those women it is certainly reasonable to replace estrogen. One needs to remember these women are often more symptomatic than women who go through normal menopause. So the objective is to treat them to improve their quality of life."
Estrogen-Only HT Not Meant for Everyone
Women who still have a uterus should not take estrogen-only hormone therapy. That's because estrogen enormously increases their risk of uterine cancer. Adding the hormone progestin to estrogen removes this risk -- but as the first arm of the WHI trial showed, it also creates other problems.
Those problems -- for older women -- include an increased risk of breast cancer, heart disease, stroke, blood clots, and dementia.
It's not clear whether other forms of estrogen and progestin besides Premarin and Prempro carry the same risks. Other forms include the skin patch and cyclic hormone therapy, which alternates weeks of hormones with weeks off hormones. However, until more is known, the FDA advises women to use all hormone therapy with the same degree of care.