Estrogen Causes Ovarian Cancer
Hormone Replacement, Ovarian Cancer Studied
Tue Apr 2, 4:02 PM ET 2002
By PAUL RECER, AP Science Writer
WASHINGTON - A study shows a modest increased risk of ovarian
cancer among women who use some forms of hormone replacement
therapy, but researchers say the findings are not strong enough to
recommend changes.
In the study, which appeared Tuesday in the Journal of the National
Cancer Institute (news - web sites), Swedish researchers report that
women using estrogen replacement therapy had a 43 percent increased
risk of ovarian cancer, while those combining estrogen with sequential
progestins had a 54 percent increased risk.
The authors, however, said that the results need to be verified by other
researchers and noted: "We advocate cautious interpretations of our
results and do not recommend changes to current (hormone
replacement therapy) prescribing practices."
In absolute numbers, the researchers said, the increased risk of cancer
was only modest. For every 1,000 women on hormone therapy, there
would be only two to three more cases of ovarian cancer, they said. In
Sweden, ovarian cancer is diagnosed in about 1 percent of women
between the ages of 50 and 75, irregardless of hormone therapy use,
the authors noted.
The study is the latest to raise questions about the common practice of
prescribing estrogen hormone supplements for women after menopause.
The hormones are taken by millions of women to combat hot flashes,
osteoporosis (the brittle bone disorder) and other complications of
menopause.
Recent studies have challenged the long-held belief that hormone
supplements ward off heart disease. Other research has linked the
hormone therapy to a slight increase in the risk of breast cancer (news -
web sites). An earlier study also linked the hormones to a modest
increase in ovarian cancer risk.
"These findings would not change the benefit-risk ratio for most
women," JoAnn E. Manson, the chief of preventative medicine at
Harvard's Brigham and Women's Hospital in Boston, said of the
Swedish study.
She said that clinical decisions about hormone replacement therapy
should be based on other factors, such as controlling hot flashes and
preventing the brittle bone disease.
"Short term use of hormone therapy for treatment of hot flashes should
not appreciably increase the risk of these cancers," Manson said. "We
can still be reassuring to most women who use the therapy for a short
time."
In the new study, eight researchers found 655 women on the Swedish
cancer registries who had epithelial ovarian cancer and 3,899
cancer-free women. The women were between the ages 50 and 74.
The researchers sent the women forms asking questions about their
history of HRT use and other factors that could affect their risk of
ovarian cancer.
By analyzing the responses, the researchers found that women who had
used estrogen alone were 43 percent more likely to have ovarian cancer
than women who did not use HRT. For women who used the estrogen
therapy along with the periodic use of progestins, another hormone,
there was a 54 percent increased risk of ovarian cancer compared to
HRT non-users. However, for women who took estrogen pills
combined with progestins there was no increased risk of the disease.
Women who were on the therapy for 10 years or more had the greatest
risk of ovarian cancer, the study concluded.
The first author of the study is Dr. Tomas Riman of the department of
obstetrics and gynecology at Falu Hospital in Sweden.
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