Estrogen receptor downregulators: new advances in managing advanced breast cancer

Breast cancer is the most frequently diagnosed malignancy in American women. Although potentially curable in the early stage, metastatic breast cancer, however, is essentially incurable. Because metastatic breast cancer is unlikely to be cured with currently available therapies, the goals of treatment in this setting are prolonging survival and maintaining or improving the quality of life. In patients with receptor (estrogen or progesterone)-positive metastatic breast cancer, endocrine therapy is generally considered the preferred first-line therapy because of the superior tolerability and the similar efficacy when compared with chemotherapy. Today a variety of endocrine therapies are available for the treatment of metastatic breast cancer, among which tamoxifen is the most widely used. Despite its proven efficacy and safety, a significant proportion of patients do not respond to tamoxifen. Further, due to its partial estrogenic activity, tamoxifen is associated with an increased risk of thromboembolism and endometrial cancer. Agents without any estrogenic activity-estrogen receptor downregulators have therefore been developed. Fulvestrant is the first clinically proven agent of this class. Oncology nurses have a key role in managing and educating patients with breast cancer. This supplement provides nurses with an overview of existing and emerging endocrine therapies for postmenopausal patients with metastatic or advanced breast cancer.