Article révisé par les pairs
Résumé : We have studied the predictive value of the estrogen receptor (ER) assay in 48 patients with advanced breast cancer with regard to the response to endocrine treatments. The significance of several clinical factors of presumed prognostic value was also analyzed. It was found that, among all variables studied, ER determination yields the most accurate prediction of the therapeutic response. Analysis by Cox’s linear logistic regression equation showed, in addition, that the probability of response is directly and positively correlated with ER concentration. The mere separation between ER-rich and ER-poor tumors is less informative and appears therefore of limited clinical and biological interest. The validity of the logistic model suggests that breast cancers are distributed along a continuous gradient of hormone dependency, as measured by their ER content. Thus, all patients are likely to benefit from endocrine therapy, even if additional chemotherapy is required for the less hormone-dependent cases. The existence of a possible synergism between endocrine therapy and chemotherapy was investigated in two clinical trials performed by the EORTC Breast Cancer Cooperative Group. The therapeutic results reported here show that, when Tamoxifen, an antiestrogen, is added to standard combination chemotherapy regimens in postmenopausal patients, the response rate rises significantly and a substantial prolongation of survival is obtained. These promising results strengthen the hypothesis developed above and lead to the adoption of a new strategy in the treatment of advanced breast cancer. Endocrine therapy used as a single treatment modality is restricted to a few accurately selected cases. On the contrary, for the majority of patients, endocrine therapy and chemotherapy used together may be considered as a first-line treatment. The compounds and schedules likely to achieve optimal synergistic combinations remain to be determined. © 1981 S. Karger AG, Basel.