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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