6th May 05:00
Studies Confirm Adverse Effects of Combination HRT (obstetrics heart cardiovascular gynecology cancer)
Studies Confirm Adverse Effects of Combination HRT
Estrogen-only formulations also implicated in breast ca, worsening of
San Diego Bureau
For anyone who held out some hope that the Women's Health Initiative
would show that combination hormone replacement therapy isn't so bad in
certain subgroups of women, that hope is fading fast.
Results from two recent studies in the New England Journal of Medicine
and one in the Lancet have mounted yet more evidence suggesting that
combination estrogen and progestin is bad for a postmenopausal
woman's heart and breasts.
In the first study, results from the final ****ysis of the estrogen plus
progestin trial of the Women's Health Initiative (WHI) make one thing
clear: estrogen plus progestin does not protect the heart. In fact, the
combination may increase the risk of coronary heart disease among
generally healthy postmenopausal women, especially in the first year
after starting hormone replacement therapy.
“Hormone therapy should not be used to prevent or treat cardiovascular
disease,” Dr. Andrew Kaunitz, professor and assistant chair of the
department of obstetrics and gynecology at the University of Florida
Science Center in Jacksonville, told this newspaper. “That's a very
clear message, and I don't think that point should be controversial
The study, which is an ****ysis of data from the WHI, found that the
risk for CHD rose 81% among women who took Prempro, the conjugated
estrogen/medroxyprogesterone acetate tablets manufactured by Wyeth
Pharmaceuticals, compared with those who took placebo. The risk subsided
over time, but at 5 years the risk for CHD still hovered around 24%.
That translates to six more cases of CHD per year among every 10,000
women using estrogen plus progestin (N. Engl. J. Med. 349:523-34,
Although he was not involved in this ****ysis, Dr. Kaunitz directs the
WHI at the University of Florida. The question of whether to commence
HRT “is all about the [woman's postmenopausal] symptoms,” he said. “For
well-informed patients, use of hormone therapy to effectively treat hot
flashes and other vasomotor symptoms remains appropriate care. But given
our evolving knowledge regarding risks, over time women on a serial
basis need to be given an opportunity and encouraged to go off HRT and
see if symptoms return or not. If they don't return, women should stay
off of HRT. If the symptoms do return, many patients in my practice will
choose to restart HRT, either at their former dose or perhaps at a lower
In a prepared statement, Dr. Victoria Kusiak, North American medical
director for Wyeth, supported this notion and recommended that hormone
therapy “be used at the lowest dose for the shortest duration consistent
with treatment goals and risks for the individual woman.”
Wyeth recently introduced two lower-dose hormone therapy products in an
effort to expand treatment options: Prempro 0.45/1.5 mg and Premarin
When the WHI study was abruptly halted last year, some clinicians
criticized investigators for using just one combination HRT product
(Prempro), leaving open the possibility that the results might be
another estrogen or progestin been used. Hope for that possibility is
In the second study from the New England Journal of Medicine,
investigators led by Dr. Howard Hodis of the University of Southern
California, Los Angeles, conducted a randomized trial of 226
with a mean age of 64 years who had at least one coronary artery lesion.
The women were randomized to usual care, estrogen therapy with
micronized 17-estradiol alone (estrogen group), or 17-estradiol plus
sequentially administered medroxyprogesterone acetate
After slightly more than 3 years of follow-up, the investigators
observed narrowing of the arteries in all study participants (N. Engl.
J. Med. 349:535-45, 2003). Women who took 17-estradiol alone were
just as likely
to experience worsening of their atherosclerosis as the other study
“This confirms other previously published, prospective, randomized
studies that have suggested that no form of HRT—whether it be estrogen
alone, or different kinds of estrogen, or estrogen plus progestin—is
protective against heart disease,” Dr. Anthony Luciano, director of the
Center for Fertility and Women's Health at New Britain (Conn.) General
Hospital, said in an interview.
In yet another blow, investigators in the Million Women Study have
concluded that women who take any hormones of any kind face a
significant increased risk for invasive breast cancer, and that the
relative risk of
breast cancer in current users increases with increasing duration of
For the study, the largest of its kind, investigators at the Cancer
Research UK Epidemiology Unit in Oxford, England, ****yzed data from
more than 1 million women aged 50-64. Women were enrolled between 1996
and 2001. Half were using HRT or had done so in the past. The ****ysis
included 9,364 cases of invasive breast cancer and 637 breast cancer
deaths, registered over 2.6 and 4.1 years of follow-up, respectively
(Lancet 362:419-27, 2003).
Of the study participants who were using HRT, 41% were taking
estrogen-only preparations, 50% were using estrogen/progestin
combinations, and 6% were using tibolone, a steroid that has similar
conventional HRT. Two percent were using an unknown type of HRT and 1%
used other preparations.
The investigators found that women using combination HRT were two times
more likely to develop breast cancer, compared with nonusers (a 100%
increase), while the risk increased by 45% among those who used
tibolone, and by 30% among those who used estrogen-only HRT.
The effects were shown to wear off within a few years of stopping
The investigators estimated that for every 1,000 women who begin 10
years of HRT at age 50 there would be 6 extra cases of breast cancer
among users of estrogen-only HRT and 19 among users of
estrogen-progestin combination HRT. The estimated extra cases of breast
cancer among tibolone users was not provided by the investigators.
They also estimated that current HRT users face a 22% increase in risk
of dying from breast cancer, compared with their counterparts who have
never used HRT.
“These are all clinically important observations,” Dr. Luciano noted.
“They support what many other smaller studies have shown. If you take
all these findings together, this provides convincing evidence that
estrogen-progestin combination therapy increases the risk of breast
cancer on a duration of therapy-related basis. At the same time,
estrogen-only therapy either has no impact on breast cancer risk or a
impact considerably less than the impact of estrogen-progestin
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