The surgical implications of estrophile protein estimations in carcinoma of the breast.

Assays of estrophile protein (ER) in 161 patients with no previous additive or ablative hormonal therapy have been analyzed; 47.2 percent were ER positive; 52.8 percent ER negative. A total of 37.5 percent of premenopausal and 50.8 percent of postmenopausal patients had ER-positive tumors. The effects of additive and ablaive hormonal therapy were observed in 75 patients; 63.5 percent of the ER-positive group and 8.6 percent of the ER-negative group responded, but the incidence in the ER-negative group is thought to be spuriously high. The level of the ER content in the ER-positive group did not influence the degree of response. The ER-negative group had a shorter life span after discovery of the tumor and was more likely to develop dominant visceral metastases. Of 15 patients followed with sequential ER assays after hormonal therapy (additive and/or ablative), 14 demonstrated substantial falls in ER levels but these did not correlate with the clinical response. Tumor assayed in nine patients after irradiation of the lesion contained no demonstrable ER. ER assays of breast cancer tissue proved to be a useful but imperfect tool in predicting clinical progress following hormonal maneuvers but some readings may be spuriously low due to imperfect techniques of measurement, prior exogenous hormonal administration or hormonal ablation, and previous irradiation of the tumor.