Postmenopausal women with persistent vasomotor symptoms (VMS) such as hot flashes and night sweats are more likely to be diagnosed with breast cancer compared with women who never experienced these symptoms; however, persistent symptoms were not associated with breast cancer-related mortality, according to a study published in Menopause.
Researchers identified 25,499 postmenopausal women aged 50 to 79 years from the Women’s Health Initiative (WHI) to examine the associations between VMS and breast cancer incidence and mortality. Breast cancer self-reports were verified by medical records, and breast cancer subtype was determined through laboratory reports. Information on VMS was collected through a questionnaire administered at baseline to assess whether participants had ever experienced hot flashes and/or night sweats; age of first and last VMS episodes was also recorded. Symptoms of VMS in the previous 4 weeks were recorded and rated as mild (no interference with usual activities), moderate (interfered with usual activities), or severe (usual activities could not be performed).
Women with persistent VMS (n=9715) were defined as those with moderate or severe hot flashes and/or night sweats within 4 weeks before WHI entry. Women were categorized as “never VMS” (n=15,784) if they denied having hot flashes and/or night sweats and reported no VMS within the last 4 weeks.
Median follow-up occurred at 17.9 years; women with persistent VMS compared with those with never VMS were younger, closer in age to menopause, more likely to be black, less likely to have received education beyond high school, and have a lower calculated risk for breast cancer (median interquartile range 1 vs 2; P <.001). Women with persistent VMS at the time of study enrollment reported symptom duration for more than 10 years.
Of the 1399 (5.5%) women with breast cancer, those with persistent VMS had a higher breast cancer incidence in comparison with women with never VMS (adjusted hazard ratio [HR], 1.13). Breast cancer incidence was greater with increasing body mass index, current alcohol use (HR, 1.26), nulliparous status (HR, 1.24), and increasing calculated Breast Cancer Risk Assessment Tool cancer risk (HR, 1.16). Women with persistent VMS were more likely to have estrogen receptor-negative cancers (P =.018) and to have regional or distant involvement (P =.002) compared with women with never VMS.
Risk of breast cancer-specific mortality was higher in women with persistent VMS vs women with never VMS (HR, 1.33). The risk of death after breast cancer was higher among older women vs younger women and in those with a family history of breast cancer. Persistent vs never VMA was not associated with breast cancer overall survival (HR, 1.02).
Women with persistent VMS, compared with women who never experienced VMS, had a higher breast cancer incidence, and the cancers were more likely to be [estrogen receptor] negative with regional or distant spread,” the authors concluded. “However, breast cancer-specific survival and breast cancer overall survival did not differ by VMS status.”
Chlebowski RT, Mortimer JE, Crandall CJ, et al. Persistent vasomotor symptoms and breast cancer in the Women’s Health Initiative [published online December 28, 2018]. Menopause. doi: 10.1097/GME.0000000000001283