Tuesday, August 10, 2010 (Last Updated: 08/11/2010)
TUESDAY, Aug. 10 (HealthDay News) -- Longer use of estrogen or estrogen-progestin therapy (EPT) is associated with a higher risk of breast cancer, with risks varying by body mass index (BMI) and tumor subtype, according to research published online Aug. 10 in Cancer Epidemiology, Biomarkers & Prevention.
Tanmai Saxena, of the University of Southern California Keck School of Medicine in Los Angeles, and colleagues analyzed data from 56,867 perimenopausal and postmenopausal women in the California Teachers Study cohort who disclosed information on hormone therapy use and other factors and were followed for a mean 9.8 years.
The researchers found that, in comparison with women who had never used hormone therapy, those who used estrogen therapy for 15 or more years had a 19 percent higher risk of breast cancer; EPT was linked to an 83 percent greater risk. Risk was highest in those using continuous combined EPT regimens. Risks were increased with length of use for women with a BMI below -- but not at or higher than -- 30 kg/m². The elevated risks were only seen for tumors positive for both estrogen and progesterone receptors and those that were human epidermal growth factor receptor 2-positive.
"The individual characteristics of a woman taking hormone therapy, such as her BMI, as well as the specific regimen of hormone therapy a woman uses, might modify the extent to which a woman's risk for breast cancer is elevated as well as the receptor profile for the malignancy. These findings, taken in context of the larger literature on this topic, continue to underscore the need to personalize risk-benefit discussions for women contemplating the use of hormone therapy," the authors conclude.
A co-author has served as a witness in litigation involving Prempro.
Hematology & Oncology
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