Estrogen receptor status as a prognostic indicator for stage I breast cancer patients.

The prognostic value of estrogen receptor determination was studied for 510 stage I (axillary node negative) breast cancer patients treated by mastectomy alone. Results at 60 months after mastectomy indicate that stage I patients whose tumors lack estrogen receptors fall into a significantly poorer prognostic group for both recurrence and survival than those whose tumors contain estrogen receptors. Within the postmenopausal group, estrogen receptor negative (ER -) patients are recurring more rapidly than estrogen receptor positive (ER +) patients. Within the premenopausal group, ER + patients have a recurrence rate identical to ER - patients, which is apparent only after prolonged follow-up. In contrast to postmenopausal ER + patients, premenopausal ER + patients appear to have no prognostic advantage over the ER - patients, and thus constitute a high risk group for which adjuvant endocrine therapy might prove beneficial.