Therapeutic effect of tamoxifen related to estrogen receptor level

Abstract

Cytoplasmic oestrogen receptor (ER) determinations were performed in 59 postmenopausal patients with metastatic breast cancer. Fifty percent of the patients were found to be ER+. Forty patients were treated with tamoxifen (TAM) and 19 patients were treated with tamoxifen plus medroxyprogesterone acetate (MPA). The response rate of TAM-treated patients was 30% (12/40). Of the 21 ER+ patients, ten (48%) responded to therapy. The ER values of these patients were significantly higher than the ER values of nonresponders (P less than 0.01). No correlation could be found between the ER value and the duration of remission in TAM-treated patients.

PIP: In this study of 59 postmenopausal patients with metastatic breast cancer, the therapeutic effect of tamoxifen (TAM) and/or TAM plus medroxyprogesterone acetate (MPA) was investigated and its effectiveness was related to the patients estrogen receptor (ER) levels. 3 studies are discussed: 1) Study 1, in which TAM was used alone; 2) Study 2, in which TAM was tested against TAM+MPA; and 3) Study 3, in which TAM was tested against TAM+diethylstilbestrol (DES). In this unselected population of post menopausal patients with metastatic breast cancer, the overall response rate to TAM treatment was 80% (12/40). Of 21 ER positive patients, 10 (48%) responded to TAM therapy. The ER values of these patients were significantly higher than the ER values of nonresponders (P .001), but no correlation was found between the ER value and the duration of remission in TAM-treated patients. These results are from the population of Studies 1 and 2; Study 3's population was too small for significant findings to be reported.