Clinical Data and Estradiol Receptor Evaluation in Breast Cancer Biopsies

Tamoxifen Efficacy in Advanced Breast Cancer Previously Treated with Endocrine and Cytotoxic Therapy

Sixty-nine postmenopausal women with disseminated breast cancer previously treated with endocrine and cytotoxic therapy were treated with tamoxifen (20 mg/day). Complete plus partial response (CR + PR) was observed in 29% (CR 16%) and stable disease in 28%. The objective response was higher in soft tissue sites (52%) compared to osseous (12 %) and visceral (13 %) disease. No regression or disease stabilization was observed in the presence of liver involvement. Free-interval, length and type of menopause, and estrogen receptor status (carried out in only 26 patients) did not statistically influence the percent of objective response. Only 1 of 16 paients (6 %) who did not respond to previous endocrine therapy responded to tamoxifen, while 3 of 9 previous hormonal responders (33 %) achieved objective regression with antiestrogen therapy. On the contrary, the response to previous chemotherapy failed to influence the subsequent response to tamoxifen. The median duration of the response was more than 12 months and the median survival more than 18 months. Treatment was generally very well tolerated and in only one patient was temporarily discontinued because of thrombocytopenia.

Relationship among estrogen receptors, proliferative activity and menopausal status in breast cancer

Kinetic and estrogen receptor (ER) determinations were performed on 357 primary breast cancers. The proliferative activity of the cell population was determined by the autoradiographic technique and expressed as [3H]thymidine labeling index (LI): the ER status was assessed by the absorption charcoal technique. From the overall analysis of the relationship between proliferative activity and ER status, by using the median LI value as cutoff of low and high proliferating tumors, a correlation between ER + status and low proliferative activity and between ER- status and high proliferative activity was observed in 64% of the cases. Menopausal status proved to be an important determinant of kinetic and ER features. In fact, the proliferative activity was always higher in ER--tumors than in ER + tumors within the same menopausal group, and a decrease in proliferative activity was observed from premenopause to postmenopause within ER + and ER--tumors. The analysis of the relation between ER levels and proliferative activity in ER + tumors also evidenced three main ER/LI clusters significantly related to premenopause, paramenopause and postmenopause. A particular indication of nodal involvement was evidenced for a cluster of tumors with low ER levels and high LI from postmenopausal patients. The three different, previously proposed kinetic groups of potential relevance for prognostic and therapeutic purposes were confirmed and more precisely defined by considering not only premenopause and postmenopause but also paramenopause.