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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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Klimakterium
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