Trends in endocrine therapy and chemotherapy for early breast cancer: a focus on the premenopausal patient

Abstract

The majority of breast cancers are diagnosed at an early stage, and treatment is focused on cure and prolonging disease-free survival. Local therapy (surgery and/or radiation treatment) is standard, along with systemic adjuvant therapy that may effectively prevent or delay relapse and death in early-stage disease. In premenopausal women, adjuvant therapeutic approaches include combination cytotoxic chemotherapy and endocrine therapy. Cyclophosphamide, methotrexate and 5-fluorouracil (CMF) was the established chemotherapy regimen; however, newer regimens have more recently been introduced that may offer some benefit over CMF including anthracycline-containing regimens [e.g. cyclophosphamide, epirubicin and 5-fluorouracil (CEF)], and taxane-containing regimens. For women with oestrogen receptor (ER)-positive disease, a second option is endocrine therapy that aims to suppress mitogenic oestrogen signalling. Until recently, 5 years of tamoxifen was regarded as the standard adjuvant endocrine treatment in ER-positive disease. Ovarian ablation is also effective in premenopausal women, and can be achieved by surgery, radiotherapy, or via the use of a luteinising hormone-releasing hormone analogue such as goserelin. Combining tamoxifen and goserelin treatment provides more effective oestrogen blockade than either drug alone. However, as the third-generation aromatase inhibitors (AIs) have demonstrated improved efficacy over tamoxifen in postmenopausal women with early and advanced disease, combination treatment with goserelin plus an AI may provide optimal oestrogen blockade in premenopausal patients. This review assesses the relative merits of chemotherapeutic and endocrine approaches for the treatment of early breast cancer, and summarises relevant ongoing clinical trials, with an emphasis on the premenopausal setting.