Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) immunohistochemistry are important markers in the management of patient with breast carcinoma. In this study, we determine the concordance rate of ER, PR and HER2 immunohistochemistry markers between core needle biopsy (CNB) and excisional biopsy (EB) of breast carcinoma in patients of Universiti Kebangsaan Malaysia Medical Centre (UKMMC) from January 2002 until December 2012. A total of 93 female patients with CNB and subsequent EB were included in this retrospective descriptive study. Immunohistochemistry is used to determine ER, PR and HER2. ER and PR was graded using Allred score (0 to 8) while HER2 was scored from 0 to 3+. The markers between these two biopsies were compared to determine the concordance rate. In ER and PR, 93 samples were compared. ER was concordant in 80 cases (86.0%) and 13 cases (14.0%) was discordant. PR was concordant in 82 cases (88.2%) and discordant in 11 cases (11.8%). In HER2, 87 samples were compared and 62 cases (71.3%) were concordant while 25 cases (28.7%) were discordant. Concordance between CNB and EB was high for ER and PR. However, concordance rate for HER2 immunohistochemistry was less consistent. Overall, immunohistochemical analyses of CNB reflect the tumour marker status of the excised specimen.
Keywords: breast carcinoma, core needle biopsy, estrogen receptor, progesterone receptor, HER2