Do hot flashes have a silver lining? Turns out they may correlate with lower odds of developing breast cancer, according to a controversial report in the February issue of Cancer Epidemiology, Biomarkers and Prevention.
The study found that women with a history of menopausal symptoms – including hot flashes, insomnia and mood swings—have a 50 percent lower risk of developing the two most common types of postmenopausal breast cancer. In addition, the more severe the hot flashes, the less likely it was that the women in the study went on to develop breast cancer. Women with the most extreme flashes—which woke them up at night—had a 70 to 80 percent lower risk of breast cancer, says senior author Christopher I. Li, MD, PhD, a breast cancer epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle.
What’s the hypothesized link between breast cancer and hot flashes? Hormones. For the last two decades, researchers have surmised that higher levels of estrogen increase your risk of breast cancer. During perimenopause and menopause, your estrogen levels fluctuate, moving in a downward direction until they settle at a much lower point than when you were, say, age 30. The assumption in the Seattle study is that hot flashes and similar symptoms indicate lower levels of estrogen, and hence a reduced risk of breast cancer.
However, not everyone agrees with that assumption. “There is no data to show that lower estrogen levels correlate with the severity of hot flashes,” says Mary Jane Minkin, MD, clinical professor of obstetrics, gynecology and reproductive sciences at Yale University. “Twenty percent of women have zero hot flashes and their estrogen levels are very low—just as low as their sister who has miserable hot flashes.” Notes Steven R. Goldstein, MD, professor of obstetrics and gynecology at New York University’s Langone Medical Center, “For younger [perimenopausal] women, the culprit in symptoms might not be just the absolute value of estrogen but the change in their estrogen levels.”
Goldstein, who is the president of the North American Menopause Society (NAMS), also takes issue with the methodology of the Seattle study. The researchers interviewed 1,437 postmenopausal women (988 diagnosed with breast cancer and 449 who had no history of the disease) and asked them to recollect years later the severity of their hot flashes, the duration of the episodes, the type of symptoms experienced, and similar details. Since the study was retrospective—women had to recall their symptoms during one 90-minute interview—rather than prospective—in which researchers would have followed what happened to the subjects over several years, “you have to take it all with a grain of salt,” Goldstein says.
Still, Margery Gass, MD, the executive director of NAMS and a consultant to the Cleveland Clinic, calls the study’s findings “thought-provoking.” She adds: “Can hot flashes be a marker for other health issues? These findings should prompt other researchers to look at their results to see if they can confirm or refute these findings.”
Experts agree, however, that this study will not change how doctors and women handle the detection of breast cancer. “There isn’t really anything women can do other than continue to get regular breast cancer screenings regardless of whether they have menopausal symptoms,” Li says.
Here’s the schedule: The American Society of Obstetricians and Gynecologists recommends that women between the ages of 40 and 50 get screened every one to two years; women 50 years and older should undergo mammograms annually.