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 colleagues.
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.