SEATTLE Women who have experienced hot flushes and other symptoms of menopause may have a 50 percent lower risk of developing the most common forms of breast cancer than postmenopausal women who have never had such symptoms, according to a recent study by researchers at Fred Hutchinson Cancer Research Center.
The results of the first study to examine the relationship between menopausal symptoms and breast cancer risk are available online ahead of the February print issue of Cancer Epidemiology Biomarkers and Prevention.
The protective effect appeared to increase along with the number and severity of menopausal symptoms, according to senior author Christopher I. Li, M.D., Ph.D., a breast cancer epidemiologist in the Hutchinson Center's Public Health Sciences Division.
"In particular we found that women who experienced more intense hot flushes the kind that woke them up at night had a particularly low risk of breast cancer," he said.
Li and colleagues suspected a link between menopause misery and decreased breast cancer risk because hormones such as estrogen and progesterone play an important role in the development of most breast cancers, and reductions in these hormones caused by gradual cessation of ovarian function can impact the frequency and severity of menopausal symptoms.
"Since menopausal symptoms occur as hormone levels fluctuate and drop, we hypothesized that women who experienced symptoms such as hot flushes and night sweats particularly frequent and severe symptoms might have a lower risk of breast cancer due to decreased estrogen levels," he said.
Indeed, the researchers found a 40 percent to 60 percent reduction in the risk of invasive ductal and invasive lobular carcinoma the two most common types of breast cancer among women who experienced hot flushes and other symptoms. The association between such symptoms and decreased cancer risk did not change even after the researchers accounte
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Fred Hutchinson Cancer Research Center