Response to endocrine therapy and breast cancer differentiation.

The purpose of this study was to determine whether aspects of tumour differentiation are associated with response to endocrine therapy in patients with advanced breast cancer. The features studied were the histological type, grade, and elastosis content of the primary tumours, and the disease-free interval. Statistically significant associations were observed between response to endocrine therapy and histological grade and disease-free interval. In addition, statistically significant associations were observed between histological grade and elastosis and disease-free interval. It is concluded that tumours which are more highly differentiated have a better chance of responding to endocrine therapy.