Adjuvant Endocrine Treatment in Premenopausal Early Breast Cancer

The impact of endocrine therapies in the adjuvant treatment of premenopausal patients with early breast cancer is well established. However, the right combination and duration of endocrine manipulations currently available (luteinizing hormone-releasing hormone analogs and tamoxifen) remain unclear. Moreover, the role of chemotherapy in addition to endocrine therapies is not clearly defined. The most recent Early Breast Cancer Trialists’ Collaborative Group overview has confirmed the efficacy of five years of tamoxifen in reducing the annual recurrence rate and the annual breast cancer death rate by 41 and 34%, respectively, in an estrogen receptor-positive population. These results are largely irrespective of age, use of chemotherapy or other tumor features. Moreover, the expert panel of the St. Gallen Conference accepted both tamoxifen or tamoxifen plus ovarian suppression as standard endocrine therapy for premenopausal breast cancer patients with endocrine-responsive disease. The use of ovarian suppression or ablation also significantly reduced the risk of breast cancer-related death, mainly in the absence of other systemic therapies. Chemotherapy is widely used in this population; however, its role in endocrine-positive premenopausal women with hormone-positive disease treated with optimal endocrine therapy remains unclear.