Hot flushes and other symptoms of menopause may give women a significantly lower risk of developing the most common types of breast cancer, and the more severe the symptoms, the lower that risk, revealed US researchers this month when they published the results of the first study ever to examine the link.
You can read about the study, by researchers at the Fred Hutchinson Cancer Research Center in Seattle, Washington, in the February print issue of Cancer Epidemiology Biomarkers and Prevention, which was available online ahead of print early January.
Senior author Dr Christopher I. Li, a breast cancer epidemiologist in the Hutchinson Center’s Public Health Sciences Division, and colleagues, concluded that compared to postmenopausal women who have never experienced them, women who have hot flushes and other menopause symptoms may have a 50 per cent lower risk of developing the two most common forms of breast cancer, invasive ductal and invasive lobular carcinoma.
Plus, as Li told the press:
“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.”
In fact, the researchers found a 40 to 60 per cent reduction in the risk of invasive ductal and invasive lobular carcinoma among women who had these symptoms, and this did not change when they took into account other known breast cancer risk factors such as obesity and use of hormone replacement therapy (HRT).
The researchers suspected there might be such a link because estrogen, one of the hormones which along with progesterone is responsible for the miserable symptoms of menopause that kick in as ovulation drops, also plays a role in the development of most breast cancers.
Previous studies have found that women who experienced symptoms during menopause had lower levels of estrogen compared to women who do not experience them. However, until this study, none had explored the link between menopausal symptoms and breast cancer risk.
For the National Cancer Institute funded study, the researchers interviewed 1,437 postmenopausal women living in and around Seattle. 988 of the women had been diagnosed with breast cancer and 449 had not, these were the controls.
They asked the women questions about symptoms as they approached and entered the menopause, including for example intensity and frequency of hot fluses, night sweats, insomnia, vaginal dryness, irregular and heavy periods, anxiety and depression.
Li said the study suggests there may be a silver lining to the menopause, which is normally associated with having a negative impact on women’s quality of life.
He said if these findings are confirmed by further studies, then “they have the potential to improve our understanding of the causes of breast cancer and improve approaches to preventing this disease”.
“Relationship between Menopausal Symptoms and Risk of Postmenopausal Breast Cancer.”
Yi Huang, Kathleen E. Malone, Kara L. Cushing-Haugen, Janet R. Daling, and Christopher I. Li.
Cancer Epidemiology Biomarkers and Prevention, Published Online First 6 January 2011.
DOI: 10.1158/1055-9965.EPI-10-0998
Additional source: Fred Hutchinson Cancer Research Center (press release, 25 Jan 2011).
Written by: Catharine Paddock, PhD