S8 Endocrine Responsiveness: Understanding How Progesterone Receptor Can be Used to Select Endocrine Therapy

Adjuvant endocrine therapies for postmenopausal women with early breast cancer: Standards and not

Hormonal manipulations have been used for more than 100 years for the treatment of metastatic breast cancer and after definition of the concept of micro-metastases also in the adjuvant setting. In the postmenopausal population, tamoxifen has played the most important role for almost four decades. Progestins or the first generation of aromatase inhibitors (AIs) were only marginally used in the adjuvant setting due to their prohibitive toxicity. The new generation of anti-estrogen compounds, the selective estrogen receptor down-regulators (SERDs) like fulvestrant have a higher affinity for the estrogen receptor than tamoxifen, but none of its agonist activities, and have shown promising clinical activity in the treatment of advanced breast cancer. The third generation of AIs investigated in six large trials has been reported to be superior to tamoxifen in terms of disease-free survival, but not in terms of survival. These trials will be discussed in terms of results in different subpopulations and of toxicity.