How to improve endocrine therapy of breast cancer

The characteristics of endocrine therapy have made it a standard therapy in metastatic breast cancer. Principles for endocrine therapy in the advanced situation are discussed. Recent overviews have shown a definite, although limited effect also in the adjuvant situation. Three possible ways for further improvement of endocrine therapy are discussed. Firstly, the relevance of results with endocrine therapy in advanced disease for the adjuvant situation is challenged. It is suggested that the most meaningful parameter to look for in the metastatic situation might still be the response rate. Secondly, the question is raised of more reliable predictors of effect of endocrine therapy. A possible model for testing in a neoadjuvant setting in operable cancers is suggested. Thirdly, selection criteria for drugs used in endocrine treatment are discussed, in relation to proven efficacy and short-term and long-term toxicity. As endocrine therapy in the future will probably be more frequently used in patients with better prognosis, the aspect of long-term toxicity will be of major concern.