A Study to Evaluate Exemestane Tablets Combined With Ovarian Function Suppression/Ablation in Treatment of Premenopausal Breast Cancer Patients With CYP2D6*10 Mutations （STEP）

This is a multicenter, randomized, open-label, parallel, active-controlled superiority clinical study conducted in early premenopausal estrogen-receptor positive breast cancer patients with CYP2D6\*10 mutations. The efficacy and safety of Exemestane Tablets combined with ovarian function suppression/ablation and Tamoxifen Tablets combined with ovarian function suppression/ablation in the treatment of early premenopausal estrogen-receptor positive breast cancer patients with CYP2D6\*10 mutations are compared.