Abstract PR10: Menopausal female hormone use in relation to risk of estrogen receptor positive and estrogen receptor negative breast cancer in African American women: Findings from the AMBER consortium

Abstract

Abstract Background: Previous studies, mostly of white women, have found that female hormone supplements, particularly medications that combine estrogen with progestin, are associated with an increased risk of breast cancer. We examined the use of estrogen alone and estrogen combined with progestin in relation to risk of estrogen receptor-positive (ER+) and ER-negative (ER-) breast cancer in a large combined analysis of data from African American women. Methods: Questionnaire data from two cohort (Black Women's Health Study, Multiethnic Cohort Study) and two case-control (Carolina Breast Cancer Study, Women's Circle of Health Study) studies of breast cancer in African American women were harmonized as part of the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. Female hormone use was examined among post-menopausal women age 40 and older. ER+ (n=1,486) and ER- (n=638) cases were compared with 8,425 controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated in polytomous logistic regression analysis with adjustment for study, age, year, geographic region, education, age at menopause, type of menopause, body mass index, oral contraceptive use, family history of breast cancer, parity, age at first birth, alcohol use, and smoking. Results: 37% of women had ever used estrogen alone and 17% had ever used estrogen plus progestin. Use of estrogen plus progestin, relative to never use, was associated with increased risk of ER+ breast cancer (OR=1.43, 95% CI 1.22-1.68). ORs were highest for long duration use (10+ years) and for recent use. The positive associations were also stronger in women with body mass index less than 25 and women age 60 and older. Length of time between menopause and initiation of hormone therapy did not modify the association. By contrast, use of estrogen alone was not associated with ER+ cancer (OR=1.02, 95% CI 0.88-1.17). There were no significant associations of estrogen alone or estrogen plus progestin with ER- breast cancer. Conclusions: Use of combination menopausal hormone supplements was associated with increased risk of ER+, but not ER-, breast cancer among African American women. These results are consistent with findings from studies of white women. This abstract was also presented as Poster B42. Citation Format: Emma Viscidi, Lynn Rosenberg, Chi-Chen Hong, Melissa A. Troester, Elisa V. Bandera, Christopher A. Haiman, Laurence N. Kolonel, Andrew F. Olshan, Christine B. Ambrosone, Julie R. Palmer. Menopausal female hormone use in relation to risk of estrogen receptor positive and estrogen receptor negative breast cancer in African American women: Findings from the AMBER consortium. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr PR10.