Abstract P3-01-05: Influence of hormone replacement therapy following bilateral salpingo-oophorectomy on mammographic breast density in women newly diagnosed with breast cancer
Authors: Pivo S , Schwartz S , Chun J , Guth A , Axelrod D , Shapiro R , Schnabel F 
Published: May 2019

Background: Studies have demonstrated that use of hormone replacement therapy (HRT) in post-menopausal women results in increased breast density. This is associated with increased risk of breast cancer and reduced sensitivity of mammography. The purpose of the present study was to compare breast densities of women following surgical menopause with and without use of HRT to women who had natural menopause without use of HRT.

Methods: Our institutional Database was queried for post-menopausal women newly diagnosed with breast cancer from 01/2010 to 01/2016. Patients were divided into following groups: 1) natural menopause with no HRT use, 2) history of a bilateral salpingo-oophorectomy (BSO) with no HRT use, 3) history of a BSO with HRT use prior to diagnosis, or 4) history of BSO and use of HRT at the time of diagnosis. BSO may have occurred with or without concurrent hysterectomy.

Results: 1106 women were eligible for analysis. 976 (88%) had natural menopause with no HRT, 63 (6%) had a BSO with no HRT, 51 (5%) had a BSO with previous history of HRT, and 16 (1%) had a BSO and were using HRT at time of malignancy diagnosis. Though not statistically significant, women who had a prior BSO and were on HRT at the time of diagnosis had more dense breasts (69% heterogeneously or extremely dense) than women who had natural menopause with no HRT (44% heterogeneously or extremely dense). However, women who had a prior BSO and were on HRT in the past had significantly less dense breasts (p=0.007) than women who underwent natural menopause without HRT use (67% vs. 56%). There were no differences observed in the tumor characteristics between all groups.

Breast densities by groupVariablesNatural menopause, no HRT (N=976, 88%)BSO, no HRT (N=63, 6%)p-valueBSO, prior HRT (N=51, 5%)p-valueBSO, current HRT (N=16, 1%)p-valueMedian age at diagnosis, yr64 (39-95)64 (39-93)0.4865 (45-83)0.3462 (41-77)0.17Median age at menopause, yr51 (33-62)47 (32-60)&lt;0.000146 (30-59)&lt;0.000147 (39-55)&lt;0.0001Breast densityEntirely fatty94 (10%)5 (8%)0.950 (0%)0.0070 (0%)0.17Scattered fibroglandular448 (46%)30 (47%) 34 (67%) 5 (31%) Heterogeneously dense393 (40%)25 (40%) 16 (31%) 11 (69%) Extremely dense41 (4%)3 (5%) 1 (2%) 0 (0%) 

Conclusion: In our study cohort, women with history of surgical menopause who were on HRT at the time of breast cancer diagnosis had a trend towards more dense breasts. Surprisingly, women who were prior users had less dense breasts than women who never used HRT. Despite the change observed in breast density, the tumor characteristics do not differ with HRT usage, suggesting that variability in breast density did not correlate with stage of disease at presentation. This may be related to heightened awareness among clinicians regarding risk associated with HRT use that led them to modify screening and surveillance in these patients.

Citation Format: Pivo S, Schwartz S, Chun J, Guth A, Axelrod D, Shapiro R, Schnabel F. Influence of hormone replacement therapy following bilateral salpingo-oophorectomy on mammographic breast density in women newly diagnosed with breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-01-05.