Effect of the Women's Health Initiative study publication on hormone replacement therapy use among women who have undergone BRCA1/2 testing

Background: Since the publication, in July 2002, of the Women's Health Initiative (WHI) study, use of hormone replacement therapy (HRT) has decreased substantially in the general population. However, little is known about the effect of WHI study results on HRT use among women at high risk of breast cancer. The purpose of this study is to compare HRT use, prepublication versus postpublication of the WHI study, among women tested for BRCA1/2 mutations. Methods: Participants were > 35 years of age and had received their result of genetic testing (delivered within the interdisciplinary research program Interdisciplinary Health Research International Team on Breast Cancer Susceptibility), no later than February 28, 2005. HRT use was reported in self-administered questionnaires, 1 year after result disclosure. Women returning their questionnaire before July 17, 2002 were classified as pre-WHI, whereas those returning it after October 15, 2002 comprised the post-WHI group. Results: Four hundred fifty-seven women (199 and 258 in the pre-WIH and post-WHI groups, respectively) were included in this analysis. Globally, there was no difference in HRT use between prepublication and postpublication of the WHI study (8% and 11%, respectively; prevalence ratio, 0.74; 95% confidence interval, 0.43-1.28). However, noncarriers of the familial mutation were less likely to use HRT after publication of the WHI study results (9%) than before (21%; P = 0.03). Conclusions: Overall, HRT use among women tested for BRCA1/2 mutations is relatively low and apparently uninfluenced by the WHI study findings. However, the HRT use reduction among noncarriers is similar to that of women in the general population and consistent with the Canadian Cancer Society's recent HRT use recommendations.