Analysis of the concordance rates between core needle biopsy and surgical excision in patients with breast cancer.

Objective: To evaluate whether immunohistochemical marker studies performed on core needle biopsy (CNB) specimens accurately reflect the marker status of the tumor obtained from final surgical specimen.
Methods: This was a retrospective study that used the database of the Division of Mastology of the Hospital das Clínicas, São Paulo, Brazil. Sixty-nine patients submitted to ultrasound-guided CNB diagnosed with breast cancer were retrospectively analyzed. Immunohistochemistry (IHC) on core biopsy specimens was compared to that of excisional biopsy regarding estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 gene (HER2), p53, and Ki67. The analysis of the concordance between CNB and surgical biopsy was performed using the kappa (k) coefficient (95% CI).
Results: A perfect concordance between the labeling in the surgical specimens and the preoperative biopsies in p53 (k = 1.0; 95% CI: 0.76-1.0) was identified. There was an almost perfect concordance for ER (k = 0.89; 95% CI: 0.65-1.0) and a substantial concordance for PR (k = 0.70; 95% CI: 0.46-0.93). HER2 (k = 0.61; 95% CI: 0.38-0.84) and Ki-67 (k = 0.74; 95% CI: 0.58-0.98) obtained a substantial concordance this analysis.
Conclusion: The results of this study indicate that the immunohistochemical analysis of ER, PR, Ki-67, and p53 from core biopsy specimens provided results that accurately reflect the marker status of the tumor. The concordance rate of HER2 was less consistent; although it produced substantial concordance, values were very close to moderate concordance.