Researchers looking into the long-term health
effects of hormone replacement therapy said on Wednesday they had made the
strongest case yet that the pills raise the risk of breast cancer.
But other experts and one company that makes hormone replacement therapy
(HRT) pills said they still dispute the conclusion that a recent drop in U.S.
breast cancer cases means that HRT was responsible for the disease.
All the experts agree that HRT can be used by women suffering severe
menopause symptoms, but they should use the lowest possible dose for the
shortest period of time.
The findings stem from the Women's Health Initiative study, which found
in 2002 that women taking HRT had higher rates of breast cancer, stroke and
heart disease.
Women stopped taking the drugs wholesale and sales plummeted. A few years
later, breast cancer rates dropped and some experts held this out as evidence
that HRT caused breast cancer.
Dr. Rowan Chlebowski of the Los Angeles Biomedical Research Institute and
other researchers reanalyzed data that showed this and said the relationship is
real. They also looked at data on 41,449 women enrolled in another Women's
Health Initiative study.
Some had argued that a 5 percent drop in the rates of mammogram screening
were in fact responsible for the drop in breast cancer diagnoses, but
Chlebowski's team report in the New England Journal of Medicine that they find
no evidence of this.
"The increased risk of breast cancer associated with the use of estrogen
plus progestin declined markedly soon after discontinuation of combined hormone
therapy and was unrelated to changes in frequency of mammography," they
concluded.
"The difference in frequency of mammography use of 2 percent between 2002
and 2003 for women using hormones is insufficient to account for the 43 percent
reduction in the incidence of breast cancer," they wrote.
Most of the women in the study had been taking Prempro, a combined
estrogen-progesterone pill made by Wyeth.
"We don't believe the article supports the theory that the decline in use
of estrogen plus progesterone caused a one-time abrupt nationwide decline in
breast cancer incidence," Wyeth spokeswoman Gwendolyn Fisher said in a telephone
interview.
"They don't offer an explanation of why breast cancer rates remain stable
today when HRT rates continue to decline," she added.
The International Menopause Society agreed.
"The decline in breast cancer rates started at least 3 years before the
Women's Health Initiative study was halted," the group said in a statement.
"Breast cancer takes years to develop and, to reach the stage where it is
detectable, it takes at least a decade. If HRT use causes breast cancer, then
the drop in breast cancer rates would not be seen for some time yet."
(Editing by Philip Barbara) Keywords: CANCER HORMONES/
(Maggie.Fox@Reuters.com; 1 202 898 8492)
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