Breast Cancer Rates Lower With Less Hormone Therapy: Study11/30/10
TUESDAY, Nov. 30 (HealthDay News) -- Reduced use of hormone
replacement therapy (HRT) is linked to declines in rates of
invasive breast cancer and ductal carcinoma in situ, the most
common form of noninvasive breast cancer, a new study reports.
The University of California, San Francisco, study included
nearly 700,000 women, aged 40 to 79, who underwent more than 2
million screening mammography examinations between January 1997 and
Women aged 50 to 69 had the highest level of hormone therapy use
and also had the largest reduction in invasive breast cancer when
they stopped hormone therapy -- from 40 cancers per 10,000
mammograms in 2002 to 31 cancers in 2005, and 35 cancers in 2006,
the investigators found.
The study also found a sharp drop in rates of ductal carcinoma
in situ in this age group after they stopped using hormone
A parallel decrease in these types of breast cancer also
occurred among women older than 70. However, there was no change in
breast cancer rates during the study period among women aged 40 to
49, who were less likely to have been on hormone therapy.
The researchers said their findings suggest that hormone therapy
helped promote breast cancer tumor growth.
"We show that the incidence of breast cancer decreases if you take the hormones away. The fact that we're continuing to see a decrease in invasive [breast] cancer means that the effects of stopping the hormones may be long-lasting," senior author Dr. Karla Kerlikowske said in a university news release.
The study was released online in advance of publication in an
upcoming print issue of the
Journal of Clinical Oncology.
The U.S. National Cancer Institute has more about
hormone replacement therapy and cancer.
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