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)

1. 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)

2. Check MMG Density via Volpara After 1yr TMX (At1yrMD) Check menopausal status after 1yr TMX(Menstruation episode or FSH <30)

3. MMG Density Reduction(MDR =BaMD-AtMD ) at 1yr

4. MDR ≥5% -> Keep go on TMX MDR <5% -> 1:1 randomization -> Keep go on TMX vs OFS add on to TMX

5. Analysis : 5yr MDR (1'endpoint), 5yr DFS(2'endpoint), 5yr OS

6. 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