Quantitative image analysis of estrogen receptors in breast fine needle aspiration biopsies

OBJECTIVE: To establish whether the results of quantitative evaluation of estrogen receptors (ERs) in cytologic fine needle aspiration (FNA) biopsies of the breast are comparable to the results obtained on excised breast tumors and therefore suitable for making a clinical decision on tamoxifen treatment in women who are not candidates for surgery. STUDY DESIGN: We performed a retrospective review of 118 breast FNA specimens that were positive for adenocarcinoma cells, had adequate cell block cellularity and provided subsequent surgical resection tissue. Quantification of ERs was performed on cell block material and follow-up tissue sections by the Chromavision Automated Imaging System, San Juan Capistrano, California, U.S.A. RESULTS: Quantitative image analysis provided consistently reliable, comparable results when evaluating for the presence or absence of ERs (at a 5% staining cutoff level), with 98.3% agreement between FNA cytology and histology specimens. Quantitative measurements of FNA samples showed the best agreement with the values derived from the subsequent surgical specimens at high-end (> 85% staining) and low-end (< 10% staining) values. However, a direct linear correlation of values was not observed. In the great majority of parallel measures, ERs were either strongly positive (> 75% staining) or had a zero value, particularly in the surgical specimens, with more "in-between" values identified in FNA specimens. CONCLUSION: Quantitative image analysis of FNA of ER results are comparable to those of surgical excision specimens and can be used for therapeutic decision making. The utility and advantages of quantitative ERs by image analysis include providing the patient and physician with important early prognostic and diagnostic information before planning a surgical approach. Additionally, FNA ERs are useful in determining therapy alternatives in patients who are not surgical candidates and in evaluating the preoperative hormone status of patients receiving chemotherapy prior to surgery.