PROGNOSTIC-SIGNIFICANCE OF ESTROGEN-RECEPTORS IN 405 PRIMARY BREAST CANCERS - A COMPARISON OF IMMUNOHISTOCHEMICAL AND BIOCHEMICAL METHODS

Over the last few years, estrogen receptor determination by means of i mmunohistochemistry has been extensively used. The aim of this study w as to compare this technique with estrogen receptor determination by m eans of dextran-coated charcoal, and to evaluate whether one of the tw o methods is more predictive of prognosis. Estrogen receptors were det ermined by means of both the dextran-coated charcoal method and immuno histochemistry in 405 patients with primary breast cancer; age, pathol ogical tumor size, nodal status, and progesteron receptors by dextran- coated charcoal method were also recorded. The disease-free and overal l survival probabilities were estimated using the product-limit method ; Cox's proportional hazard model was used to evaluate the prognostic role of estrogen receptors as determined by the two methods. There app ears to be a close association between estrogen receptor determination by the two methods (81.5% of concordant results) and their prognostic role was similar, even when the patients were divided into different groups (on the basis of their estrogen receptor status) and adjustment s for the effect of other prognostic variables were taken into account . Our study shows that the two methods can be used indifferently to ev aluate estrogen receptor status as a prognostic factor in breast cance r patients.