Hormone Replacement Therapy

Definition
History
Health Benefits
Concerns and contraindications

Definition

The logic behind HRT is straightforward: if menopausal symptoms and certain illnesses emerge from a lack of estrogen, replenishing the body's supply of estrogen can prevent or reverse these problems.

History

Estrogen replacement therapy (ERT) won the confidence of clinicians in the early 1950's when studies documented that estrogen could alleviate many menopausal symptoms and had a beneficial effect on bone density. By the mid 1970's, a serious side effect began to emerge: researchers demonstrated a significantly higher occurrence of endometrial cancer (a type of uterine cancer) among long-term users of "unopposed estrogen" (estrogen taken without a progestin). As a result of this frightening news, the majority of women did not receive HRT. For those women who did, it was usually for short periods of time. Long-term therapy was reserved for women with early menopause or osteoporosis.

By the 1980's, it became clear that estrogen combined with an adequate amount of progestin could counteract the negetive effects on the uterus. It is well known that estrogen stimulates growth of the endometrium. When administered with an appropriate dose and duration, progestins can effectively block, and even reverse the estrogen effect. This information, combined with the increasing knowledge and awareness that menopausal HRT can have major beneficial effects on bone and cardiovascular health, and may also have a role in preventing Alzheimer's Disease and colon cancer, has made HRT again accepted not only as treatment for menopausal symptoms, but also an important arsenal in preventive medicine.


Benefits of HRT

The "hot flash" is cooled considerably by HRT. At the current time there is no better treatment to alleviate this symptom. Over 90% of women will experience a complete cessation or a marked decrease in the severity and frequency of hot flashes after initiating estrogen.

The vagina and outflow tract of the bladder are extremely sensitive to estrogen. Painful intercourse, annoying vaginal infections and some urinary incontinence problems can be completely eradicated with estrogen therapy. Local application of estrogen creams is as effective for these problems as systemic (oral or transdermal) treatment. However vaginal treatment with estrogen will not address the issues of osteoporosis or heart disease.

The first important medical benefit of HRT that was recognized is the impact of estrogen on bones. HRT can halt, or markedly slow down the process of bone loss, thereby reducing the risk of a vertebral and hip fracture by up to 50%. However, the likelihood of osteoporosis and fractures increases rapidly with advancing age. Thus, if a woman wishes to prevent osteoporosis, she needs to start therapy as early after menopause as possible and continue for at least 10 years. Two to 3 years of estrogen in the early menopausal period will not yield enough protection for the elderly years. Although it was initially recognized that HRT was a good preventive measure for osteoporosis, only recently was it found to be therapeutic for those women who have already suffered an osteoporotic fracture. When treated with estrogen, these women will esperience less future fractures than those women who are not treated in such a manner.

Heart disease is prevalent among women and is the most common cause of death among menopausal women in many western nations. Thus, any treatment that reduces the risk or delays the onset of heart disease has a major impact on the overall health and well-being of women. Essentially all observational studies have demonstrated a 30-50% decrease in the incidence of heart attacks among estrogen users. The greatest benefit occurs while a woman is taking HRT. The protective effects decrease progressively over time after a woman discontinues therapy. Women with cardiovascular disease benefit to an even greater degree than women who are without heart disease.

There is some evidence that estrogen affects cognition and mood. The most severe form of a cognitive disorder is Alzheimer's disease, a progressive disease of the nervous system that leads to memory loss and a decline of intellectual and motor capabilities. Population studies have found a decreased incidence, or a delayed onset of Alzheimer's disease among women who have taken HRT. Studies are also under way to evaluate whether estrogen may be offered as treatment for women suffering from Alzheimer's disease.

Although the mechanism remains unknown, there are a number of studies emerging that suggest a decreased incidence of colon cancer among estrogen users.


Concerns and Contraindications

Despite all of the positive effects of HRT, only 10-20% of menopausal women are taking it. The 2 most common concerns that women cite are the continuance of vaginal bleeding and their concerns of cancer.

There are 2 ways that HRT can be prescribed: cyclic or continuous. The cyclic regimen mimics the normal menstrual cycle. Estrogen is taken daily and for a 10-14 day period of time a progestin is also administered. With this form of treatment, 90% of women can expect to have "periods." The continuous method involves taking both the estrogen and a lower dose of the progestin on a daily basis. The daily progestin prevents a build-up of the endometrium (the uterine lining). The absence of endometrial growth results in no vaginal bleeding in up to 90% of women on continuous HRT, hence a major advantage. When taken as prescribed, both regimens have proven effective in reducing the risks of endometrial cancer. If a woman has had a hysterectomy (a surgical removal of the uterus), progestins do not need to be prescribed. The only exception to this rule is the woman who has extensive residual endometriosis after a hysterectomy.

For most individuals, the fear of cancer is a strong emotion. The cancers that may be provoked by HRT are uterine (endometrial) and breast cancer. The increased risk of uterine cancer has been essentially eliminated with a proper understanding of how progestins protect against excessive endometrial growth. However, it is important to remember that proper progestin administration is not a guarantee that one will never develop endometrial cancer. Progestins are prescribed to eliminate the increased risk that occurs with "unopposed estrogen." Remember even women who have never taken HRT do develop endometrial cancer. Thus, if abnormal bleeding occurs in a woman on HRT, she deserves the same evaluation to rule out cancer as a woman who has never taken HRT.

Breast tissue is also responsive to estrogen and progestin, thus raising the concern of breast cancer and HRT. Many studies have been performed worldwide and the results are controversial. These contradictory findings have contributed to the confusion that both physicians and patients experience. Some studies have found a link between postmenopausal HRT and breast cancer, while others have not. What is clear is that short-term use of estrogen does not increase a woman's risk of breast cancer. Ten years or more of therapy may be associated with a 20-30% increase in the risk. To translate this into something that is understandable, instead of 10 in 100 women developing breast cancer, it would be 12 or 13 women. Although frightening for most women, it is important to put these risks into perspective. Four to 5 percent of women die of breast cancer, but 40-50% of women die of heart disease. There is also some evidence suggesting that the women who are diagnosed with breast cancer while taking estrogen may have improved survival when compared to non-estrogen using women.

There are a few "absolute contraindications" to HRT, or conditions when estrogen should not be prescribed. Most physicians will not administer HRT to women who have had a personal history of estrogen-responsive tumors, namely endometrial and breast cancer. It may be of interest to know that some researchers are beginning to question the validity of this long held dogma. Studies are currently underway to evaluate whether a subset of these cancer survivors may be able to take HRT without increasing their risk of recurrent disease.

If a woman has active liver disease, hormonal therapy should not be prescribed. Women with a remote history of liver disease, followed by complete restoration of normal liver function can take HRT. Any undiagnosed vaginal bleeding needs to be thoroughly evaluated to exclude the possibility of a cancer before initiating HRT. Finally, if a woman has developed a clot in her blood vessels in association with altered hormonal states (i.e., pregnancy, use of birth control pills) or is currently afflicted with a clotting problem, she should not be prescribed HRT.

No matter which health problem a person encounters, it will have a major impact on her quality of life and longevity. Therefore, each individual woman needs to weigh the risks and benefits of HRT in regard to her own past medical history, as well as familial tendencies. HRT is not the fountain of youth. It is another form of preventive medicine with the intent to enhance the likelihood of a longer, healthier and productive life. The decision to take HRT can be a difficult one. But in collaboration with a physician, the best decision can be made.


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