Breast Cancer Cases in Canada Drop With Decrease in HRT
THURSDAY, Sept. 23 (HealthDay News) -- A decline in breast
cancer rates among postmenopausal women in Canada earlier this
decade coincided with a decrease in the use of hormone replacement
therapy, a new study shows.
Researchers analyzed national data and found that "the nearly 10
percent drop in invasive breast cancer rates coincided with the
decline in use of hormone replacement therapy reported among
Canadian women aged 50 to 69 years."
The largest decrease in hormone therapy occurred between 2002
and 2004, when use fell from 12.7 percent to 4.9 percent. During
that same period, there was a 9.6 percent decline in breast cancer
incidence, said Prithwish De, of the Canadian Cancer Society, and
Their study appears online Sept. 23 in the
Journal of the National Cancer Institute.
The drop in breast cancer incidence "is likely explained by the
concurrent decline in the use of hormone replacement therapy among
Canadian women," the researchers said in a journal news
Hormone therapy use decreased dramatically in several countries
after the release in 2002 of a U.S. study that showed the health
risks of hormone therapy outweighed the benefits.
The researchers noted that breast cancer rates among
postmenopausal women in Canada began to rise again in 2005. This
may be further evidence of a connection between hormone therapy and
breast cancer, they said.
"Such a rebound might be expected if [undetected] hormone-sensitive tumors were merely slowed by the withdrawal of hormone replacement therapy rather than prevented by it. If so, hormone replacement therapy may be thought to act as a promoter, rather than a cause of breast cancer," the researchers said in the release.
The U.S. National Institute of Child Health and Human
Development has more about
hormone replacement therapy.
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