Abstract P1-02-06: Improved survival with ovarian function suppression in premenopausal hormone receptor-positive breast cancer: a propensity score matching of ASTRRA-trial participants with single-center postmenopausal patients

Abstract Background: Poor survival outcome in young women with hormone-sensitive breast cancer was reported. And previous studies have demonstrated that the addition of ovarian function suppression (OFS) significantly improved disease-free survival (DFS) in patients with premenopausal hormone receptor–positive breast cancer. In this study, we examined whether ovarian function suppression treatment in premenopausal women is effective in survival comparable to postmenopausal status. Methods: We evaluated 1,298 breast cancer patients included in the post-trial follow-up of the Addition of Ovarian Suppression to Tamoxifen in Young Women With Hormone-Sensitive Breast Cancer Who Remain Premenopausal or Regain Vaginal Bleeding After Chemotherapy (ASTRRA) trial who received either tamoxifen (TAM) only (n=647) or TAM + OFS (n=635), randomly assigned in a 1:1 ratio and postmenopausal patients in AMC (Asan Medical Center; Seoul, Korea) treated with aromatase inhibitor (AI) (n=603). All patients analyzed in this study underwent surgery between March 2009 and November 2011. The primary endpoint was disease-free survival (DFS) and the secondary endpoint was overall survival (OS). We use propensity-score matching by lymph node status, tumor size, tumor grade, histologic type of cancer, human epidermal growth factor receptor-2 (HER2) status, chemotherapy regimen, surgical modality, and radiotherapy in the overall cohort and in separate subgroups according to anti-hormonal therapy regimens. Results: In the overall matched cohort, there was a significant difference between the postmenopausal AI group and premenopausal Tam only group in DFS (hazard ratio for the postmenopausal AI group, 0.654; 95% CI, 0.432 to 0.991) and OS was not significantly different between the premenopausal Tam only group and postmenopausal AI group (p=0.061). On the other hand, there was no significant difference between the postmenopausal AI group and premenopausal Tam+OFS group in disease free survival (hazard ratio for the postmenopausal AI group, 1.156; 95% confidence interval [CI], 0.735 to 1.820) or the overall survival (hazard ratio for the postmenopausal AI group, 1.04; 95% CI, 0.553 to 1.956). Conclusion: This study’s findings suggest that the poor prognosis of young women with hormone-sensitive breast cancer is improved by adding OFS to Tam and the effect is not inferior to that of using AI in post-menopausal women. Outcomes in a Cohort of Patients Matched for Propensity Scores postmeno AI, postmenopausal patients who treated with aromatase inhibior in Asan Medical Center; premeno Tam+OFS, premenopausal ASTRRA participants who treated with tamoxifen and ovarian function suppression; premeno Tam, premenopausal ASTRRA participants who treated with tamoxifen only Citation Format: Young-jin Lee, Tae-Kyung Yoo, Sae Byul Lee, Jisun Kim, Il-Yong Chung, Beom Seok Ko, Jong Won Lee, Byung Ho Son, Sei Hyun Ahn, Seonok Kim, Hee Jeong Kim. Improved survival with ovarian function suppression in premenopausal hormone receptor-positive breast cancer: a propensity score matching of ASTRRA-trial participants with single-center postmenopausal patients [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-02-06.