[363] ER, PR, and Her2 Immunocytochemistry on Cell-Transferred Cytologic Smears of Breast Carcinoma – A Study with Comparison to Formalin-Fixed Tissue

Jill A Ferguson, Pierce Chamberlain, Howard H Wu. Indiana University School of Medicine, Indianapolis, IN

Background: The presence of ER, PR, and Her2 can be used to predict response to treatment in patients with primary or metastatic breast carcinoma. Fine needle aspiration (FNA) can provide cellular material which may be used for such analysis. Formalin-fixed cell blocks (CBs) have been used for this purpose; however, CBs sometimes lack adequate cellularity even when the direct smears are highly cellular. The aim of this study is to assess the reliability of ER, PR, and Her2 status as demonstrated by immunocytochemistry (ICC) on slides made from alcohol-fixed direct smears using the cell transfer (CT) technique.
Design: A computerized search of the laboratory information system was performed. FNA cases diagnosed as primary or metastatic breast carcinoma in which ICC for ER, PR, and Her2 had been performed either on a CB or a concurrent biopsy were identified over an 18 month period (January 2010 through July 2011). All correlating cytology and surgical pathology reports were reviewed as well as selected slides. ICC for ER, PR, and Her2 was performed on alcohol-fixed direct smears using the CT technique. The results were compared to those reported for the corresponding CB or biopsy.
Results: A total of 47 FNA specimens from 46 patients were included in the study. ICC for ER, PR and HER2 were scored as recommended by CAP/ASCO guidelines. ICC results were excluded from the study if the CT smear contained less than 50 cells. Correlation between the ICC on the CT smears and the corresponding CB or biopsy revealed a sensitivity rate for ER, PR, and Her2 of 95%, 90%, and 88% respectively with a specificity of 100% for all 3 markers. There were 4 cases in which the ICC for Her2 on the CT smear was scored as 2+ (equivocal), of which 2 were negative and 2 were equivocal on the corresponding CB or biopsy. There was 1 case in which the ICC for Her2 on the CT smear was scored as 1+ in which the corresponding biopsy was equivocal for Her2. These 5 cases were excluded from calculation of sensitivity and specificity for Her2.
Conclusions: ICC performed on FNA smears using the cell transfer technique is useful in the assessment of ER, PR, and Her2 status, especially when the direct smears are highly cellular and the CB lacks adequate cellularity. The specificity is 100% for all 3 markers and the sensitivity is high with a rate of 95%, 90%, and 88% for ER, PR and HER2 respectively.
Category: Cytopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 78, Tuesday Morning

 

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