A decline in breast cancer rates among postmenopausal women in Canada previous 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 enveloping 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 occurrence, said Prithwish De, of the Canadian Cancer Society, and colleagues.
Hormone therapy use decreased radically 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 amongst 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 return 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 substitute therapy may be thought to act as a promoter, rather than a cause of breast cancer," the researchers said in the release.
Researchers analyzed national data and found that "the nearly 10 percent drop in enveloping 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 occurrence, said Prithwish De, of the Canadian Cancer Society, and colleagues.
Hormone therapy use decreased radically 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 amongst 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 return 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 substitute therapy may be thought to act as a promoter, rather than a cause of breast cancer," the researchers said in the release.
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