THURSDAY, Oct. 5 (HealthDay News) -- Circulating levels of sex steroid hormones may be important in the etiology of premenopausal breast cancer, according to a study in the Oct. 4 issue of the Journal of the National Cancer Institute.
A. Heather Eliassen, Sc.D., of Brigham and Women's Hospital in Boston, and colleagues collected blood samples from 18,521 premenopausal women from 1996 to 1999, during the early follicular and mid-luteal phases of their menstrual cycles. They diagnosed 197 cases of breast cancer.
The researchers found that women in the highest quartile of follicular total and free estradiol levels had a statistically significant increased risk of breast cancer compared to women in the lowest quartile (relative risk, 2.1). They also found that women in the highest quartile of total and free testosterone and androstenedione in both menstrual cycle phases had modest, non-statistically significant increases in overall risk of breast cancer but stronger, statistically significant increases in risks of invasive cancers compared to women in the lowest quartile (RR, 2.0). Over three years, they observed 30 cases of breast cancer among women in the lowest 25 percent of follicular total estradiol levels and 50 cases among women in the highest 25 percent.
"The inclusion of premenopausal circulating hormone levels may improve breast cancer risk prediction models for premenopausal women," the authors conclude.
Abstract
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