Doctor's View Archive
Medical Author: Carolyn J. Crandall, MD, MS, FACP
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR
Hormone therapy, or HT, is often prescribed for women to ease the symptoms of menopause, i.e., hot flashes. Hormone therapy with estrogen given by mouth (oral estrogens), by a patch placed on the skin, or by certain prescription vaginal estrogen rings, can relieve menopausal hot flashes. However, due to controversies regarding the possible dangers of long-term use of oral estrogen , other methods of giving the hormone are being sought.
Potentially adverse effects of oral estrogens include pre-cancers of the uterus (tissue in the womb that may become cancerous in time) in women with an intact uterus. This risk can be counteracted completely by the use of progesterone along with estrogen. However, long-term oral estrogen use, especially in combination with progesterone, may increase the risk of breast cancer. This risk seems to begin after 5 years of use. Some doctors and the women they treat hope that giving estrogen topically, meaning through the skin, may reduce some of the potential side effects of estrogen.
The use of estrogen-containing patches may avoid some of the long-term dangers of oral estrogen, because the estrogen is not processed through the stomach. Since this theory has not been proven, it is not yet known if patches will minimize the long-term harmful effects seen with oral estrogen. Like oral estrogen, patches have been determined to cause the same harm on the uterus if they are not given with progesterone in women with a uterus. In fact, estrogen patches are prescribed along with progesterone pills to reduce the risk of uterine pre-cancers in the same way that progesterone pills are given together with estrogen pills. Furthermore, estrogen patches are proven to increase bone density, an effect that proves that estrogen patches do get absorbed and likely have a variety of hormonal effects throughout the body.
In addition to patches, the idea of hormone creams has appealed to women. Although many hormone creams are available over-the-counter, these preparations are not controlled by the Food and Drug Administration. The amount of the cream that is absorbed from these preparations varies in an unpredictable way from woman to woman. Also, because they are not subject to the same regulations as prescription medications, the strength of the cream can vary from batch to batch, even within the same brand. The health risks and benefits have not been demonstrated in rigorous (well-performed) medical research.
It would probably surprise women to know that there are only a couple of good research studies in which hormone creams have been tested. The scant research available on hormone creams has shown that progesterone cream causes blood hormone levels that vary tremendously from person to person. This means that if two different women use progesterone cream, one could absorb hormone levels that are too low and another could receive an "overdose." Some very preliminary research demonstrated that progesterone cream may help reduce hot flashes, but this research is still in the early stages. The hormone preparations used in the studies are not available to practicing physicians as a prescription medication - at least not yet.
Progesterone cream should not be substituted for oral progesterone if it is being used to protect the uterus in a woman taking estrogen because it is not known if progesterone cream provides sufficient uterus protection.
Progesterone cream that is available now is also probably not sufficient to prevent osteoporosis.
Because oral estrogen and progesterone combination, but not oral estrogen alone, increased the risk of breast cancer in the Women's Health Initiative, progesterone itself may increase risk of breast cancer. Breast cancer survivors may want to be wary of progesterone cream. Of note, many breast cancers have progesterone receptors, meaning that progesterone may trigger their growth. Whether the amounts of progesterone that are absorbed from progesterone creams are enough to raise breast cancer risk has not been determined.
A few formulations of estrogen cream and gel are available by prescription, and are effective in suppressing hot flashes. Currently, no real information is available regarding either the good, or bad health effects of these topical prescription estrogens. Research in this area is active. Women must be aware that long-term safety has not yet been studied for any estrogen or progesterone cream.
For the present, hormone creams sound attractive and may turn out to be safe and effective. However, it's simply too early to know.
For additional information, please read the Hormone Therapy article.