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June 24, 2003
The study is part of a run of bad news recently about
the hormones routinely taken by millions of women after menopause.
"Hopefully, it will convince women to reconsider," said
Dr. Susan Hendrix of Wayne State University in Detroit, a co-author
of the new analysis. "We've got to find a better way to
help women with their menopausal symptoms."
Some previous studies suggested tumors might be less aggressive
in hormone users; other studies indicated the opposite. Previous
research also suggested that hormones might make breast tissue
more dense, hindering the detection of tumors.
To try to answer the questions more definitively, the researchers
took a closer look at data from the government's landmark Women's
Health Initiative study, which was halted last summer after
it was found that estrogen-progestin pills raise the risk of
heart attack, strokes and breast cancer.
While last summer's findings led many women to stop taking
hormones, an estimated 3 million women still use them, primarily
to relieve hot flashes and other symptoms of menopause.
The findings appear in Wednesday's (June 25, 2003) Journal
of the American Medical Association.
LARGER TUMORS REPORTED
The analysis involved 16,608 women ages 50 to 79 who used either
combined hormone treatment or dummy pills for an average of
five years.
As of January, breast cancer had developed in 245 women who
used the combined hormone treatment and in 185 women who had
taken dummy pills.
Hormone users' tumors were larger at diagnosis, 1.7 centimeters
on average versus 1.5 centimeters in placebo women. Tumors
had begun to spread in 25.4 percent of hormone users, compared
with 16 percent of placebo women.
The researchers said this appears to mean that in women on
estrogen-progestin, the tumors both grow faster -- that is,
they are more aggressive -- and escape detection longer.
Overall, women on both hormones faced a 24 percent increased
risk of breast cancer -- equal to eight extra cases of cancer
per year for every 10,000 women taking the pills.
The increased risk did not appear in the first two years of
treatment. But Hendrix said the tumors may have been present
early on but were not detected until later because of hormone-induced
breast density.
The new analysis did not examine breast density. But researchers
think progestin may be the culprit because it can cause breast
cells -- both normal and abnormal -- to proliferate, an effect
that may be accentuated when the hormone is combined with estrogen,
Gann said.
Wyeth Pharmaceuticals, maker of the Prempro pills used in the
study, said hormones remain an appropriate therapy when used
at the lowest possible dose for the shortest possible time.
MOST CONCLUSIVE STUDY YET
The latest analysis is by far the most conclusive, said Dr.
Peter Gann, an associate professor of preventive medicine at
Northwestern University who was not involved in the study.
It "further worsens the news for long-term hormone replacement
therapy. It suggests the excess breast cancer risk is not trivial," Gann
said.
Last summer's Women's Health Initiative findings shattered
long-held beliefs that hormones are good for women's hearts.
Last month, another analysis of data from the study found that
instead of sharpening the mind, hormones may double the risk
of Alzheimer's and other forms of dementia.
A second, smaller study in Wednesday's journal also confirmed
a link between combined hormone treatments and breast cancer
and suggested estrogen-only treatment may be safer.
The study involved 975 Seattle-area women ages 65 to 79. The
greatest breast cancer risk was in women who used estrogen-progestin
for at least five years, even if they took the progestin component
only some days a month.
Those who used estrogen alone, even for 25 years or longer,
showed no appreciable increased risk, according to the study,
led by Dr. Christopher Li of Fred Hutchinson Cancer Research
Center in Seattle.
Estrogen alone is recommended only for women with hysterectomies
because it can cause uterine cancer unless balanced by progestin.
The researchers said more definitive answers will come from
the continuing estrogen-only part of the Women's Health Initiative
study.
© 2003 Associated Press.
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Hormonal
disorders