Tamoxifen versus tamoxifen plus doxorubicin and cyclophosphamide as adjuvant therapy for node-positive postmenopausal breast cancer: results of a Japan Clinical Oncology Group Study (JCOG9401)

Background Cancer subtype has recently become an increasingly important consideration when deciding the treatment strategy for breast cancer. For the estrogen receptor positive (ER+) subtype, the efficacy of adjuvant endocrine therapy is definitive, but that of adjuvant chemotherapy is controversial.