Efficacy of nonestrogenic hot flash therapies among women stratified by breast cancer history and tamoxifen use

Abstract

In Brief Objective: Various nonestrogenic therapies have been found to be effective in mitigating hot flashes, but it has been unclear whether the efficacy varies by whether women have had breast cancer and/or were taking tamoxifen. Methods: This study used data from Mayo Clinic/North Central Cancer Treatment Group clinical trials that evaluated the efficacy of any nonestrogenic agent for hot flashes and had information on breast cancer history or tamoxifen use. Statistically significant changes from the fourth treatment week versus the baseline week, using individual patient data, were assessed using Student's t test. Results: A total of 1,396 women from 20 hot flash studies were eligible for analysis. Overall, women without breast cancer had a similar percentage of baseline hot flash score at week 4, as did those with breast cancer (53% vs 50%, P = 0.92). Women who were not taking tamoxifen had a significantly lower percentage of hot flash score at week 4 as compared with those who used tamoxifen (54% vs 61%, P = 0.01). However, this was due to a higher reduction in hot flash scores in the placebo arms among women not receiving tamoxifen; the percentage reduction in hot flash scores at week 4 from baseline in the active therapy arms of the randomized placebo-controlled trials (ie, excluding placebo arms) was similar among the tamoxifen users and nonusers (difference in mean percentage reduction, 5.7; 95% CI, −1.76 to 13.16). Conclusions: Some nonestrogenic therapies seem to be useful for reducing hot flashes, irrespective of the etiology of hot flashes. A meta-analysis of available studies evaluated the use of nonestrogenic therapies for hot flashes in groups of participants with and without a history of breast cancer and in participants with and without the concurrent use of tamoxifen, supporting that these treatments affect hot flashes equally well in all of these participant groups.