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 < 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 < 0.05). Statistical significance remained when the patients were grouped according to menopausal status or nodal involvement (P < 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 < 0.0005). Seventy‐nine patients received chemotherapy; 52% of the ER+ and 57% of the ER‐ patients responded (P < 0.5). ER+ tumors had a predilection to metastasize in skin and bone, while ER‐ tumors metastasized more commonly to the viscera and brain.