Density Lowering Effect of "OFS Add on to TMX"(DELFINO Trial)

Density Lowering Effect of Ovarian Function Suppression in Premenopausal Breast Cancer Patients Who Had no Density Change With One Year of Tamoxifen Treatment

DELFINO tial is designed to investigate the role of "OFS add on to TMX ", based on MMG density as a surrogate marker in premenopausal women Premise - MMG density as a surrogate marker of hormone therapy Assumption - "Add on OFS to TMX" would have further decrease of density 3-arm(Observation arm + Randomised 2-arm), phase III, RCT with 1:1 allocation

Enroll : Sep03,2018~(Planned N= 224) Inclusion criteria Premenopausal ER+ Planned tamoxifen(TMX) No planned ovary function suppression(OFS) Regardless of ChemoTx Mammography(MMG) density check via Volpara*(=Baseline MMG density, BaMD) (*Volpara= software to check MMG density) Check MMG Density via Volpara After 1yr TMX (At1yrMD) Check menopausal status after 1yr TMX(Menstruation episode or FSH <30) MMG Density Reduction(MDR =BaMD-AtMD ) at 1yr MDR ≥5% -> Keep go on TMX MDR <5% -> 1:1 randomization -> Keep go on TMX vs OFS add on to TMX Analysis : 5yr MDR (1'endpoint), 5yr DFS(2'endpoint), 5yr OS Calculation of patients' number In previous study(<Kim et al. Breast Can Res 2012>) MDR (Mammography Density Reduction) was found in about 50% of all patients who received endocrine therapy. Expected MDR in "TMX only" cohort -> 6 ± 7% MDR in "OFS add on to TMX" -> 10 ± 7% after 1yr, Significance level 5%, average MDR 4% difference, 80% power, 10% dropout rate => 1:1 randomization Number = 112(56:56) Total number = 224

Inclusion Criteria: Premenopausal women, ER+ breast cancer, stage I~III, underwent standard treatment including surgery, Planned TMX available MMG density check via Volpara Exclusion Criteria: Bilateral breast cancer Prior endocrine therapy Postmenopausal status unavailable MMG density check via volpara before and after TMX