Agreement between incisional and excisional biopsies for hormone receptors and her2 in breast cancer.

Introduction: Breast cancer is the leading cause of cancer mortality in Mexican women.

Objective: The objective of the study was to identify concordances among core needle biopsy (CNB) and excisional biopsies (EB) regarding diagnosis, hormonal receptors (HR), and human epidermal growth factor receptor 2 (Her2).

Materials and methods: Core number, demographic data, histological type, and treatment were documented for each sample. Reported HR and Her2 score from both samples were compiled.

Results: 70 women with both CNB/EB were included. Median age was 58 (36-87) years; initial diagnosis in CNB were invasive ductal 56 (80%), lobular 10 (14%), and mixed 4 (6%) carcinomas. Diagnostic agreement among CNB and EB was of 97%, k = 0.65. A concordance of 92% (k = 0.75), 75% (k = 0.26), and 67% (k = 0.46) was observed for estrogen receptors, progesterone receptors, and Her2 determinations, and positive predictive values in CNB were 0.96, 0.89, and 0.44, respectively.

Conclusion: HR and Her2 concordances using manual-immunohistochemistry (IHC) were found within the range of values obtained using automatized-IHC. When compared to tumor heterogeneity, technical/reading errors contribute more to discordances.