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 only 26 patients) did not statistically influence the percent of objective response. Only 1 of 16 patients (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.