Reliance on hormone receptor assays of surgical specimens may compromise outcome in patients with breast cancer

Abstract

Purpose: To assess the concordance of breast cancer immunohistochemical receptor assays on core biopsy and surgical specimens. Patients and Methods: We identified 100 patients whose core biopsy and definitive surgical specimens were processed in our hospital. New sections, with core and surgical specimens on the same slides, were stained for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) immunohistochemistry (IHC). Two pathologists assessed the sections independently. Raw scores and clinically significant groupings were compared. Results: Concordance for ER, PR, overall hormone receptor (HR), and HER-2 status was seen in 86%, 83%, 90%..