Tamoxifen is a first-line hormonal treatment of ER-positive metastatic breast cancer. It is used for breast cancer risk reduction in women at high risk, and as adjuvant treatment of axillary node-negative and node-positive, ductal carcinoma "in situ". Tamoxifen treatment is also useful in the treatment of bone density and blood lipids in postmenopausal women. Adverse effects include hot flushes and more serious is two to three times higher relative risk of developing endometrial cancer compared to women of an age-matched population.