Breast Cancer Risk May Rise With High Hormone
FRIDAY, Oct. 21 (HealthDay News) -- Elevated levels of hormones
increase breast cancer risk in postmenopausal women, and as the
number of different elevated hormones rises, so does the risk, a
new study has found.
Researchers from Brigham and Women's Hospital and Harvard
Medical School in Boston examined levels of eight different sex and
growth hormones in blood samples collected from nurses up to nine
years before their health information was recorded.
The risk of breast cancer increased 16 percent with each
elevated hormone level, according to the study published online
Oct. 21 in the journal
Breast Cancer Research.
The investigators found that the highest levels of circulating
estrogens (estrone and estrogen), prolactin, and androgens
(testosterone, androstenedione, DHEA, or DHEA-sulfate) were each
associated with between a 50 and 200 percent increased risk of
developing breast cancer.
A woman with elevated levels of one hormone had a 10 percent
increased risk, while the risk was doubled for those with elevated
levels of five or six hormones, and tripled for those with elevated
levels of seven or eight hormones, the study authors explained in a
journal news release.
And for women with estrogen receptor-positive (ER-positive)
breast cancer, all of these risks were slightly higher, the
researchers pointed out.
"Elevated estrogens had the biggest effect on risk, especially for ER-positive cancer. However, androgens and prolactin also contribute to increasing risk of breast cancer. These hormones are known to stimulate the growth of breast cancer cells in the lab and, while androgens can be converted to estrogen in the body, these hormones have also been found to stimulate cancer cell growth in the absence of ER," Shelley Tworoger, of Brigham and Women's Hospital, explained in the news release.
"Our results suggest that models used to assess breast cancer risk could be improved by taking into account multiple sex hormone and growth hormone levels," she added.
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