Abstract PD1-06: Mammographic breast density as a predictor of hormone receptor positive breast cancer recurrence: A single centre longitudinal analysis

Abstract

Abstract Mammographic breast density as a predictor of breast cancer recurrence: a single centre longitudinal analysis of women with hormone receptor positive breast cancer Background Mammographic breast density has been associated with risk of development of breast cancer. To date clinical studies examining the use of tamoxifen and fall in mammographic breast density during this treatment have shown reduction in mammographic breast density examining change in mammographic breast density between baseline and a single follow-up mammogram to be predictive for disease recurrence. Aim To examine serial change in mammographic breast density over years to describe the changes which occur with use of aromatase inhibitors and tamoxifen, as well as changes following cessation of this treatment and to determine whether changes observed correlate with outcome. Method Eligible patients were identified from the Royal Perth Hospital breast unit database between January 1994-December 2011. Patient data was prospectively collected through the breast unit database. Additional data regarding endocrine therapy, adherence, weight, height and concomitant medications were obtained from case note review. Recurrence data was obtained from the hospital medical records system, as well as the breast unit database. Mammograms were obtained and mammographic breast density readings undertaken by a single reader using Cumulus. Percentage breast densities were obtained and statistical analysis undertaken to investigate changes in mammographic density on endocrine therapy, at switch of therapy, and cessation of therapy and correlation with disease free and overall survival. Results 1942 eligible patients were identified. 417 were premenopausal at time of diagnosis, 148 perimenopausal, 1328 postmenopausal and the remainder unknown status. 12 declined adjuvant endocrine therapy, 520 received both at least 1 aromatase inhibitor and tamoxifen during follow-up, 1189 tamoxifen only, 56 tamoxifen plus goserelin, and the remainder either aromatase inhibitor only or aromatase inhibitor with ovarian suppression. Over 10,000 mammograms were obtained for analysis. Currently results are available from 4301 mammograms from 689 patients. Mean density change between baseline scan and subsequent imaging after between 11-24 months of patient-reported endocrine adherence was -6.0%, with mean reduction of -11% in patients who were premenopausal at baseline and -4.5% in those who were postmenopausal at baseline. Kaplan Meier analysis showed late separation of overall survival curves favouring those with reduction in mammographic breast density however there was no statistically significant difference in the curves Conclusion Reduction in mammographic breast density was greatest in those who were premenopausal at baseline. Further multivariate analysis and assessment of the additional mammograms in this data set is required to assess the association between mammographic breast density and outcome in this cohort. Citation Format: Redfern AD, Martin HL, Stone J, Davidson JA, Yap F, Chung K. Mammographic breast density as a predictor of hormone receptor positive breast cancer recurrence: A single centre longitudinal analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD1-06.