Breast Hormonal Receptors Test Should Be Repeated on Excisional Biopsy After Negative Core Needle Biopsy

Therapeutic decision-making for women diagnosed with breast cancer requires accurate determination of the estrogen receptor (ER) and progesterone receptor (PR). Decisions about adjuvant therapy are often based on the immunohistochemical (IHC) profile of the core needle biopsy sample (CNB) because the staining is not repeated on the final excisional biopsy (EB). The purpose of this study was to assess the concordance of breast cancer IHC receptor assays on CNB and EB. We identified 176 patients with matching breast CNB and EB that had available ER and PR. While the CNBs were processed and stained in different laboratories, the EB were processed and stained in our institution. The following antibodies were used 1D5, 6F11 and SP1 for ER, and PgR636, 16 and 1E2 for PR, from Dako, Leica and Ventana respectively. Correlation of scores of CNBs with matching EB was analyzed using Spearman correlation coefficients. Sensitivity, specificity, overall agreement and the kappa statistic were used to measure the concordance between CNB and EB. For CNB, there were 141 (80.1%) cases positive for ER and 118 (67%) cases positive for PR. For EB, there were 143 (81.3%) cases positive for ER and 130 (73.9%) cases positive for PR. Overall agreement for ER and PR was seen in 93% (95% CI = 0.88, 0.96) and 90% (95% CI = 0.84, 0.94) respectively. Overall, ER- CNB/ER+ EB was seen in seven (4%) cases and PR- CNB/PR+ EB in 15 (8.5%) cases. ER+ CNB/ER- EB was seen in five (2.8%) cases and PR+ CNB/PR- EB in three (1.7%) cases. To avoid erroneous omission of life-saving endocrine therapy ER and PR should be repeated on the EB for patients whose CNB has negative hormonal receptors.