Clinical response and survival according to estrogen receptor levels after bilateral ovariectomy in advanced breast cancer.

Estrogen receptor levels were determined at the time of ovariectomy in 71 premenopausal women with advanced breast cancer. Three groups of estrogen receptor concentration were established: less than 10 fmol/mg cytosol protein (group 1), between 10 and 25 fmol/mg cytosol protein (group 2), and more than 25 fmol/mg cytosol protein (group 3). The frequency of clinical response to ovariectomy was low in group 1 (17.4%), high in group 3 (79.4%), and intermediate in group 2 (35.7%). Median survival was poor in group 1 (18.5 months) and better in groups 2 (33.0 months) and 3 (32.5 months). These results were independent of disease stage and neoplastic localization.