Monday, August 27, 2007
Reuters reports on recent data published in the 5th Journal of the National Cancer Institute showing a decline in breast cancer rates which appears related to a decline in the use of hormone replacement therapy.
"It's encouraging that breast cancer rates decreased with decreases in use of hormone therapy," Dr. Karla Kerlikowske told Reuters. This implies that women who stopped using hormone therapy in a relatively short period of time have a risk of breast cancer similar to women who have never used hormone therapy."
Kerlikowske from San Francisco Veterans Affairs Medical Center and the University of California, San Francisco, and colleagues examined whether parallel declines in postmenopausal HRT use and rates of breast cancer are present among women undergoing routine screening mammography.
They point out that the breast cancer detection rate is higher in women undergoing mammography, so "the proportion of women in the population undergoing routine screening mammography will influence population-based estimates of breast cancer incidence."
The prevalence of postmenopausal HRT use started to decline about the same time that observational studies in early 2000 linked use of estrogen and progestin combinations to greater breast cancer risk than use of estrogen alone. An even greater decline followed the release of the Women's Health Initiative study in 2002.
The current study involved over 600,000 screening mammograms on women 50-69 years of age, of whom 3238 had breast cancer. The rate of estrogen receptor-positive invasive cancer was stable until 2001, but declined 13 percent per year from 2001 to 2003, the report indicates. Rates of estrogen receptor-negative invasive cancer did not change during this interval. . . . .