PURPOSE: We compared trajectories of vasomotor symptoms (VMS) and their risk factors in women with breast cancer (BrCa) to those of cancer-free controls.

METHODS: Data were from 15 nearly annual follow-up visits (1996-2017) of the multi-racial/ethnic cohort of midlife women enrolled in the Study of Women's Health Across the Nation (SWAN). We compared women with incident BrCa to controls for patterns of VMS, controlling for risk factors identified in bivariate analyses using multivariable longitudinal analyses.

RESULTS: Characteristics at study entry largely did not differ between cases (n = 151) and controls (n = 2161). Adjusted prevalence of any VMS increased significantly among cases from diagnosis to 2.75 years post diagnosis [per-year adjusted odds ratio (aOR) = 1.76, 95% confidence interval (CI) 1.39-2.24], peaking at 2.75 years post diagnosis, whereas prevalence was stable among controls in this interval [aOR = 1.04, 95% CI 0.99-1.11]. Beyond 2.75 years post diagnosis, prevalence declined significantly in cases [aOR = 0.72, 95% CI 0.61-0.84] and less in controls [aOR = 0.96, 95% CI 0.92-1.00]. Patterns were similar for frequent VMS. Adjustment for tamoxifen use slightly reduced the per-year OR for any prevalent VMS post diagnosis, partially explaining excess VMS in cases. Other treatments were unassociated with VMS.

CONCLUSIONS: Patterns of prevalent VMS reporting differed significantly between cases and controls, particularly post diagnosis, the latter only partially explained by tamoxifen use among cases. Risk factors for VMS largely did not differ between cases and controls.