Persistent hot flashes linked to ‘slight but significant’ increase in breast cancer risk
Postmenopausal women who experienced persistent vasomotor symptoms, such as hot flashes and night sweats, appeared more likely to be diagnosed with breast cancer than women who never experienced those symptoms, according to findings from the Women’s Health Initiative.
“In this large group of women who were not users of hormone therapy, persistent hot flashes and night sweats for 10 or more years were associated with a slight but significant increase in breast cancer incidence,” JoAnn Pinkerton, MD, professor of obstetrics and gynecology at University of Virginia Health System and executive director of North American Menopause Society, said in a press release. “Other risk factors included an elevated BMI of more than 30 and current alcohol use. More studies are needed in women who have persistent hot flashes to understand their cardiovascular and cancer risks.”
HemOnc Today spoke with Pinkerton about the rationale for this study, how it was conducted and the implications of results.
Question: Can you provide background on prior investigations into this topic and the inconsistent results they showed?
Answer: Earlier small case-control studies looking to evaluate the association between hot flashes and breast cancer incidence showed a decreased risk among women with vasomotor symptoms. However, a larger cohort population study from Australia did not find the same association. Women who had breast cancer and developed hot flashes on aromatase inhibitors appeared to have less risk for breast cancer recurrence.
Q: How did you conduct your study?
A: This study followed more than 25,000 postmenopausal women aged 50 and 79 years who participated in the Women’s Health Initiative clinical trials and observational study. Women who did not have a negative mammogram at baseline and those taking hormone therapy were excluded from the study.
Q: What did the results show?
A: After median follow-up of 17.9 years, postmenopausal women who experienced persistent hot flashes for at least 10 years were 13% more likely to be diagnosed with breast cancer than those who did not experience vasomotor symptoms. This finding held true even after adjustment for known breast cancer risk factors, such as elevated BMI, alcohol use, cigarette smoking and family history of breast cancer. In addition, the researchers found a higher rate of poor-prognosis cancers among the women with persistent hot flashes, including breast cancers that were ER-negative or more advanced with regional or distant involvement.
Q: What are the implications of the results?
A: Even after adjustment for known risk factors, women with persistent hot flashes were more likely to be diagnosed with breast cancer, although no significant increase was found in breast cancer mortality or survival rates.
Q: What is the potential explanation for this association?
A: Additional risk factors seen in this trial included obesity, current alcohol use and never having been pregnant. Persistent hot flashes and obesity also are associated with increased risk for cardiovascular disease, suggesting that these are ongoing health risks that require the attention of women and providers.
Q: How can these results help inform patient care?
A: Persistent hot flashes have now been linked to both breast cancer risk and cardiovascular disease. Women who are overweight have another reason to work on losing weight and getting adequate exercise. The recommendation is 30 minutes of exercise five times per week.
Q: Should these results be a factor when making decisions about breast cancer risk assessment or screening?
A: Women who have persistent hot flashes should stay up to date with breast cancer screening — both mammograms and breast exams — to increase the chances for early detection.
Q: What should be next for research on this topic?
A: Larger prospective studies are needed to understand this increased risk for breast cancer with long-term persistence of hot flashes. A study comparing women who experience no bothersome hot flashes with those with different durations of hot flashes would help to define the population at risk, and evaluation can show if there are differences in blood hormone levels or other factors that can help explain who is at risk and why. – by Jennifer Southall
Chlebowski RT, et al. Menopause. 2018;doi:10.1097/GME.0000000000001283.
For more information:
JoAnn Pinkerton, MD, can be reached at University of Virginia Health System, 1215 Lee St., Charlottesville, VA 22908; email: firstname.lastname@example.org.
Disclosure: Pinkerton reports no relevant financial disclosures.