Abstract
Tamoxifen (ICI 46474) was given by mouth to patients with advanced, recurrent, or metastatic breast carcinoma. At a dosage of 10 mg twice daily 60% of patients showed arrest or reversal of tumour growth. At a dosage of 20 mg twice daily 77% showed arrest or reversal of tumour growth. Side effects were usually trivial and their incidence was the same at both dose levels. No patients showed virilization of fluid retention.