Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor-2 Testing in Breast Cancer: Assessing the Value of Repeated Centralized Testina in Excision Specimens

摘要

Breast cancer is the most commonly diagnosed non-cutaneous malignancy in American women.1 Current recommendations call for the determination of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 neu (HER2/neu) status on all newly diagnosed cases of breast cancer,2'3 so that patients can be assessed for the possibility of various adjuvant and neoadjuvant therapies. In the United States, the first conclusive diagnosis of breast cancer is most commonly rendered on the core needle biopsy, and these tests are accordingly performed thereon a priori.4 Previous studies have shown a high, but imperfect concordance between the biopsy and excision when ER, PR, ? and HER2/neu status is determined on the same tumor in both specimens.5'6 In one meta-analysis of 27 studies, the pooled sensitivity of ER, PR, and HER2 status in the biopsy (using the status of these proteins on the excision as criterion standard) were 97%, 91.1%, and 79.9%, respectively.5 In similar analysis of 21 studies, the pooled sensitivity and specificity were 97.3% and 82.0%, respectively, for ER and 92.3% and 76.5%, respectively, for PR.6 This small but significant discordance between biopsy and excision specimens regarding ER, PR, and HER2/neu status has largely been attributed to intra-tumoral phenotypic heterogeneity and associated factors, such as large tumor size or tumor multifocality,7"15 and has formed the basis for retesting the excision specimen under some specific scenarios.