Abstract P4-14-15: Prospective study analyzing value of breast Density change predicting ENdocrine therapy response in postmenopausal women taking adjuvant ARomatase inhibitor [DEAR study] (interim analysis)

Abstract

Abstract Objective : To evaluate the value of breast density change of mammography and breast MRI as a predictive marker for a response to postoperative anti-hormone therapy by targeting ER-positive postmenopausal breast cancer patient Methods : Density change of mammography, breast MRI density being taken just before start of anti-hormone therapy, mammography being performed after 6 months, 1 year, 2 years thereafter and breast MRI being performed 1 year after start of therapy will be measured by volpara and 3D-MR method. Molecular profile including ER expression level that has a relation with response rate to anti-hormone therapy will be analyzed and outcome will be evaluated based on disease free survival and overall survival. Recurrence rate of each group was estimated based on the data of the patients in breast center of Seoul National University Hospital, 2006-2011, who underwent surgery of ER-positive breast cancer. Among 1065 persons, 7.5% (80/1065) showed recurrence rate and among these, recurrence rate of patients who took AI was 6.9% (12/175). Among these, based on MDR 5% cutoff, 1.6% vs 9.8% was represented. By designating recurrence rate as 1.5%, 9.5% and assuming dropout rate by refusal to clinical test as 10%, registration goal was set at total 411 persons based on each 137, 274 persons per each group. Results : (this is interim analysis) From 2012, total 156 patients are enrolled, among them, 32 patients were eliminated (affirmative consent, switched to Tamoxifen, recurrence and etc). From now total 124 patients are on-going to this study. Compare with Non AI group, breast density change of AI group is much decreased from base line study and it is statistically significant. (1 year follow up – base line, 2 year follow up– base line ; -12.2%, - 18.6% vs - 7.6%, -15.3% P-value 0.002, 0.009 respectively) Only one patient was relapsed within 5 year and there were no death. Psychological anxiety, medication compliance and side effects analysis were done. Psychological anxiety about disease and medication were improved as time goes by (p<0.001). But medication compliance and side effects of AI were worsen. (p = 0.178, 0.015 respectively) Other topics will analyze. (DFS and OS, etc.) Discussion : 70% of breast cancer is ER-positive breast cancer. Endocrine therapy (ET) has been clarified as an effective target therapy in large scale, prospective randomized trial and up to the present, it has been settled down as a standard therapeutic method of ER-positive breast cancer. As a result of 20 years' follow-up after intake of AI (aromatase inhibitor) and 20 years' follow-up after intake of tamoxifen, recurrence was represented as 2-2.5% and at present, clear mechanism of such resistance and predictive biomarker have not been clarified. Due to this resistance, all the ER-positive breast cancer patients are forced to receive anti-hormone therapy for 5 years or 10 years. According to the taking AI, breast density is significantly decreased compare Non AI group. Of course need more follow up data and analysis, but we can confirm a meaning of endocrine responsiveness of breast density change being measured after anti-hormone therapy as predictive surrogate. Citation Format: Kim Y, Lee E, Lee H-B, Kim KE, Ju YW, Jung JG, Moon H-G, Noh D-Y, Han W. Prospective study analyzing value of breast Density change predicting ENdocrine therapy response in postmenopausal women taking adjuvant ARomatase inhibitor [DEAR study] (interim analysis) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-15.