Abstract P5-12-11: Duration of ovarian function suppression for premenopausal women with hormone receptor-positive breast cancer: Retrospective study

Background: Although tamoxifen (TAM) plus ovarian function suppression (OFS) is one of standard adjuvant treatments in premenopausal women with hormone receptor-positive breast cancer, the optimal duration of OFS has not been clearly established. Patients and Methods: We retrospectively reviewed data of premenopausal patients with breast cancer, who received TAM and OFS (goserelin or leuprorelin) as adjuvant therapy between February 2004 and April 2015. The primary analysis was to compare disease-free survival (DFS) between patients who received OFS shorter than 3 years and those who received OFS longer than 3 years. The analyses were performed with Cox proportional hazards models and propensity score matching models. Results: We analyzed 206 premenopausal patients with hormone receptor-positive breast cancer. Median follow-up time was 56 months. Median age was 42 years (range, 24-52 years). Twenty six per cent of the patients had positive axillary nodes and 30% had received neo-adjuvant or adjuvant chemotherapy. Median duration of OFS was 26 months. Duration of OFS was shorter than three years (OFS 3y) in 26% patients. Patients with node-positive disease were more in OFS > 3y group than in OFS 3y group than in OFS 40 years were 91.8% and 99.0%, respectively (p=0.0223). Propensity score matching model showed that DFS was not significantly different between patients in OFS 3y group (97.4%, 91.6%; p=0.2406). In patients aged ≤ 40 years and/or those who received chemotherapy, 5-year DFS was 96.7% in OFS 3y group (p=0.3011). Conclusions: Our data suggest that OFS 3y for premenopausal women with hormone receptor-positive breast cancer as adjuvant endocrine therapy. A randomized trial is needed to establish the optimal OFS duration for these patients. Citation Format: Ozaki Y, Tamura N, Utiyama M, Masuda J, Koganemaru S, Miura Y, Tanabe Y, Ogura T, Kadowaki M, Miura D, Kawabata H, Takano T. Duration of ovarian function suppression for premenopausal women with hormone receptor-positive breast cancer: Retrospective study. [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 P5-12-11.