ESTROGEN-RECEPTORS IN 699 PRIMARY BREAST CANCERS - A COMPARISON OF IMMUNOHISTOCHEMICAL AND BIOCHEMICAL METHODS

Background: Over the last few years, estrogen receptor (ER) determinat ion by immunohistochemistry (ERICA) has been extensively used, but it still remains to be established whether this method can replace the st andard biochemical technique using dextran-coated charcoal (ERDCC). Pa tients and methods: ER were determined by both the dextran-coated char coal (DCC) method and immunohistochemistry (ICA) in 699 patients with primary breast cancer; other parameters (age, pathological T-pT-and no dal status-pN-, progesterone receptors by DCC, proliferative index by ICA) were also recorded. The 'best' cut-off for ERICA was evaluated by means of Receiver Operating Characteristics (R.O.C.) analysis; logist ic regression analysis was used to find adequate 'weights' for stain i ntensity. Results and conclusions: A significant correlation was found between the two methods (p < 0.001). R.O.C. analysis revealed that th e 'best' cut-off for the ERICA score was 45% (sensitivity 0.810, speci ficity 0.804). Logistic regression analysis showed that an ERICA score which also considers staining intensity does not add any useful infor mation concerning ER content in breast cancers.