Effect of EDTA decalcification on estrogen receptor and progesterone receptor immunohistochemistry and HER2/neu fluorescence in situ hybridization in breast carcinoma.

Bone is the most common site of metastasis in breast carcinoma (BC). Treatments for metastatic BC depend on various factors, including the tumor's estrogen receptor (ER), progesterone receptor (PR), and HER2 status. Bone biopsies require decalcification which may affect the accuracy of ER and PR immunohistochemistry (IHC) and HER2 situ hybridization (FISH) studies. Ethylenediaminetetraacetic acid (EDTA) decalcifying solutions have been theorized to have no significant impact on ER and PR IHC or HER2 FISH analyses. We completed a prospective study of the effect of EDTA decalcification on ER and PR IHC and HER2 FISH in 29 cases of BC. Samples from 29 BC resections were collected and formalin fixed between 12 and 24 h. Control samples were routinely processed, whereas test samples were placed in EDTA for 48 h. ER and PR slides were blinded, randomized, and evaluated. Blinded samples underwent HER2 FISH assays where an average HER2 copy number and HER2/CEP17 ratio were calculated. Paired differences between EDTA and control samples were compared for ER and PR positivity, average HER2 copy number, and HER2/CEP17 ratios using paired-samples t-tests (PST) and Wilcoxon signed-rank test (WSR). PST and WSR tests yielded no significant difference between EDTA and control tissue for ER% (PST: P = 1; WSR: P = 0.916), PR% (PST: P = 0.973; WSR: P = 0.984), HER2 copy number (PST: P = 0.124; WSR: P = 0.103), and HER2/CEP17 ratio (PST: P = 0.25; WSR: P = 0.105). The use of EDTA in bony tissue is therefore a valid decalcification method to ensure accurate assessment of ER and PR IHC and HER2 FISH in metastatic BC.

Assessment of cytotechnologist-cytopathologist interpretative agreement using the Bethesda system for reporting thyroid cytopathology.

BACKGROUND: The Bethesda system for reporting thyroid cytopathology was proposed to provide a clinically relevant framework for interpretations to improve interobserver agreement. Limited data is available regarding the level of interobserver agreement between groups of cytotechnologists (CTs) and cytopathologists (CPs) examining the same thyroid fine needle aspirate (FNA) samples. METHODS: Retrospective review of 1,229 thyroid FNAs from 976 patients between 03/2010 and 08/2012 was performed. FNAs received preliminary evaluation by a CT followed by final interpretation by a CP. We calculated Cohen's Kappa coefficient to measure agreement between CTs and CPs, and analyzed levels of discrepancy using delta analysis. RESULTS: Overall Kappa between CTs and CPs was 0.79 (95%CI: 0.76-0.83). Kappa values were higher for the nondiagnostic (0.89), benign (0.83), and malignant (0.91) categories than for other categories. Overall Kappa did not show a trend over time, and inversely correlated with the percentage of intermediate grade lesions (coefficient of -0.8; P < 0.01). CTs overcalled more cases (n = 71) than undercalled (n = 29) (P < 0.001), as compared to CPs, with a Δ1 ratio of 2.2 and Δ2 ratio of 3.5. Most two-level discrepancies were related to follicular lesions (19/21) (P = 0.0002). Differences in sample adequacy assessment occurred in 2% of cases. CONCLUSION: Overall, there was a high level of interpretative agreement between CTs and CPs, which remained stable over time, including judgments regarding specimen adequacy. Agreement was most robust for the benign and malignant categories. Our data supports the current practice of allowing CTs to perform on-site adequacy evaluation of thyroid FNAs.