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Q. What is the purpose of the WHI study on combination
hormone therapy?
A. The long-term studies in the WHI were initiated
because over the years a number of research studies
presented a complicated picture of the risks and
benefits of hormone therapy, and its continued use for
prevention of cardiovascular diseases was
controversial. This situation led the NIH to conduct a
large clinical trial of the risks and benefits of
hormone therapy. The WHI set out to examine the
long-term effect of estrogen plus progestin on the
prevention of heart disease and hip fractures, while
monitoring for possible increases in risk for breast
and colon cancer. The estrogen plus progestin regimen
was given to women who have a uterus since progestin
is known to protect against endometrial cancer, a
known effect of unopposed estrogen. A separate study
of estrogen alone in women who had a hysterectomy was
also begun.
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Q. Why were the women in the WHI
estrogen-plus-progestin study told to stop study pills
in July 2002?
A. When it reviewed the study data in May 2002, the
WHI Data and Safety Monitoring Board saw an increased
risk of breast cancer in women taking estrogen plus
progestin. The Board also saw that the previously
identified risks for heart attacks, strokes and blood
clots to the lungs and legs had persisted. Therefore,
in the judgment of the Board, the overall risks
outweighed the benefits of taking estrogen plus
progestin.
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Q. What were the main findings in the WHI study on
estrogen-plus-progestin?
A. The main findings show that compared to women
taking placebo pills:
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The number of women who developed breast cancer was
higher in women taking estrogen plus progestin.
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The numbers of women who developed heart attacks,
strokes, or blood clots in the lungs and legs were
higher in women taking estrogen plus progestin.
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The numbers of women who had hip and other fractures
or colorectal cancer were lower in women taking
estrogen plus progestin.
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There were no differences in the number of women who
had endometrial cancer (cancer of the lining of the
uterus) or in the number of deaths.
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Q. What are the increased risks for women taking
estrogen-plus-progestin?
A. For every 10,000 women taking estrogen plus
progestin pills:
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38 developed breast cancer each year compared to 30
breast cancers for every 10,000 women taking placebo
pills each year.
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37 had a heart attack compared to 30 out of every
10,000 women taking placebo pills.
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29 had a stroke each year, compared to 21 out of
every 10,000 women taking placebo pills.
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34 had blood clots in the lungs or legs, compared to
16 women out of every 10,000 women taking placebo
pills.
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Q. What are the reduced risks for women taking
estrogen-plus-progestin?
A. For every 10,000 women taking estrogen plus
progestin pills:
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10 had a hip fracture each year, compared to 15 out
of every 10,000 women taking placebo pills each
year.
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10 developed colon cancer each year, compared to 16
out of every 10,000 women taking placebo pills.
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Q. What are the conclusions from these findings?
A. The main conclusions are:
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The estrogen plus progestin combination studied in
WHI does not prevent heart disease.
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For women taking this estrogen plus progestin
combination, the risks (increased breast cancer,
heart attacks, strokes, and blood clots in the lungs
and legs) outweigh the benefits (fewer hip fractures
and colon cancers).
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Q. What were the actual hormones that women in the
estrogen-plus-progestin study were taking?
A. Women who were randomized to receive active
hormones were taking conjugated equine estrogens 0.625
mg each day and medroxyprogesterone acetate 2.5 mg
each day.
This is the most commonly prescribed postmenopausal
hormone therapy in the United States for women who
have a uterus (used each day by more than six million
women).
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Q. When did the increased risk of breast cancer become
apparent for women taking estrogen-plus-progestin
compared to women taking placebo pills?
A. There was no difference in the development of
breast cancer during the first 4 years between women
taking estrogen plus progestin and those taking
placebo pills. After that time, the numbers began to
increase. After an average of 5.2 years, there was an
increased risk of breast cancer in women taking
estrogen plus progestin compared to those taking
placebo pills.
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Q. Do you have recommendations about other hormone
alternatives (lower-dose estrogens, micronized
progesterone, natural hormones)?
A. We cannot make specific recommendations about other
hormone medications, such as different estrogens or
progestins. We also cannot make recommendations about
hormones women take in lower dosages or in different
ways, such as patches instead of pills.
Futher, without scientific clinical trial data, one
cannot assume that alternative estrogen plus progestin
treatments are any safer than those studied in WHI.
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Q. I am taking prescription hormones, what should I
do?
A. We recommend that you talk with your health care
provider about your individual health risk profile and
the hormones you are currently taking.
The FDA's advice on hormone therapy should be
considered.
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Q. Does this information apply to Selective Estrogen
Receptor Modulators (SERMS) or phytoestrogens?
A. These preparations were not studied in the WHI
Hormone Program, and therefore, we cannot make any
conclusions about the risks or benefits of SERMs, such
as raloxifene (Evista®) or tamoxifen (Nolvadex®) or
phytoestrogens.
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Q. How does this information affect my decision to use
HT for relief from hot flashes, sleep problems and
mood swings?
A. The WHI and the observational studies on the risk
of ovarian cancer were long-term studies which were
not meant to address the shorter-term use of HT. Thus,
the information from these studies should be used by
women considering use of HT for longer than 3 or 4
years.
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