Estrogen receptor: a prognostic factor in breast cancer.

Two-hundred-seventeen women with primary breast carcinoma had an estrogen receptor determination tested by both the dextran-coated charcoal assay and sucrose density gradient. The results were correlated with the disease-free interval, survival, response to hormone therapy or chemotherapy, and site of recurrent disease. The disease-free interval (DFI) was significantly longer in premenopausal patients with estrogen receptor positive (ER+) determination compared with premenopausal patients with estrogen receptor negative (ER-) determinations, irrespective of nodal involvement (P less than 0.05). There was no difference between the postmenopausal patients. The survival of the ER+ patients was statistically longer than that of the ER- patients (P less than 0.05). Statistical significance remained when the patients were grouped according to menopausal status or nodal involvement (P less than 0.002 or less). Sixty-two patients were treated with hormonal therapy, either ablative or additive. Forty-eight percent of patients with ER+ responded compared with 6% of patients with ER- (P less than 0.0005). Seventy-nine patients received chemotherapy; 52% of the ER+ and 57% of the ER- patients responded (P less than 0.5). ER+ tumors had a predilection to metastasize in skin and bone, while ER- tumors metastasized more commonly to the viscera and brain.