Background: Fine Needle Aspiration (FNA) is an increasingly utilized diagnostic modality for diagnosing metastatic breast carcinoma. Evaluation of hormone receptor status in the setting of metastatic breast disease is standard of practice. There is limited data assessing the hormone receptor status of metastatic breast carcinoma in FNA specimens, particularly with regards to cell transfer techniques when there is inadequate tumor volume in the cell block.
Design: All FNA cases diagnosed as primary or metastatic breast carcinoma from 2010-2014 were reviewed. When performed at the time of original diagnosis, immunocytochemical stain interpretations of Estrogen Receptor (ER), Progesterone Receptor (PR), and HER2 by either cell transfer or cell block techniques were recorded. Cell transfer was performed on cases in which insufficient tumor material was present in the cell block.
Results: Hormone receptor immunocytochemical stains were attempted in 56% (163/291) of FNA specimens diagnosed as primary (4/291) or recurrent/metastatic (287/291) breast carcinoma. Immunocytochemical interrogation was performed by cell transfer technique in 24 (15%) cases and by cell block evaluation in 139 (85%) cases. Among all cases in which immunocytochemical stains were attempted, results were issued in all but 10 (6%) cases in which tumor cellularity was deemed too low (8 cell blocks and 2 cell transfers) for hormone status assessment. ER, PR, and HER2 were positive in 62%, 37%, and 18% of tumor cells, respectively.
Conclusion: Hormone receptor status of metastatic breast carcinoma can be reliably assessed by FNA and immunocytochemistry utilizing both cell block and cell transfer techniques. Cell transfer provided 15% of the cases with biomarker results that otherwise would not have been performed due to inadequate cellularity in the cell block.
Fine Needle Aspiration (FNA) is a safe, minimally invasive, and relatively inexpensive diagnostic method which may be used for the evaluation of both primary and metastatic breast carcinomas. While a diagnosis can often be made primarily based on cytomorphologic features (Figure 1), adjunctive tools such as Immunocytochemistry (ICC) and Fluorescence In Situ Hybridization (FISH) are often required to assess for the presence or absence of Estrogen Receptor (ER), Progesterone Receptor (PR), and Human Epidermal Growth factor 2 (HER2) in breast carcinomas, findings of which have well established prognostic and therapeutic implications [1]. FNA can provide cellular material which may be used for determining the ER, PR, and HER2 status of both primary and metastatic breast carcinomas. The detection of these markers on FNA samples has been studied on direct smears, cytospin slides, liquid-based preparations, cell block sections and cell-transferred cytologic smears with variable success rates [2-8]. There is limited data assessing the hormone receptor status of metastatic breast carcinoma in FNA specimens, particularly with regards to cell transfer techniques when there is inadequate tumor volume in the cell block.
Figure 1: FNA smear of metastatic ductal carcinoma of the breast (Papanicolaou stained, x400).
Hormone receptor immunocytochemical stains were attempted in 56% (163/291) of FNA specimens diagnosed as primary (4/291) or recurrent/metastatic (287/291) breast carcinoma. Immunocytochemical interrogation was performed by cell transfer technique in 24 (15%) cases and by cell block evaluation in 139 (85%) cases. Among all cases in which immunocytochemical stains were attempted, results were issued in all but 10 (6%) cases in which tumor cellularity was deemed too low (8 cell blocks and 2 cell transfers) for hormone status assessment. The ICC studies for ER, PR and HER2 were successfully performed in 160/163 (98%), 158/160 (99%) and 148/155 (95%) of FNA samples and ER, PR, and HER2 were positive in 99/160 (62%), 59/158 (37%), and 26/148 (18%) of cases, respectively (Table 1).
Positive | Negative | Equivocal | Insufficient cells | Total cases | |
ER | 99 | 61 | 0 | 3 | 163 |
PR | 59 | 99 | 0 | 2 | 160 |
HER2 | 36 | 90 | 32 | 7 | 155 |
The status of ER, PR and HER2 in breast carcinoma is very important as a prognostic factor and is essential for the selection of appropriate treatment. It is recommended that hormone receptor and HER2 testing be performed on all primary breast carcinomas and on recurrent or metastatic tumors [9-12]. The initial diagnosis of primary breast carcinoma is typically rendered by image-guided stereotactic core biopsies. However, for metastatic/recurrent breast carcinoma, FNA is a safe and cost effective method to obtain diagnostic materials. In the setting of metastatic breast cancer, obtaining adequate tumor volume by FNA for hormone receptor assessment and HER2 status is of utmost importance. Testing for ER, PR, and HER2 by immunohistochemistry has been developed for use on formalin-fixed, paraffin-embedded tissue obtained by surgical biopsies, and the American Society of Clinical Oncology/College of American Pathologists guidelines recommend using only tissue samples fixed in 10% phosphate buffered formalin for HER2 testing [13]. Previous studies have demonstrated that Immunocytochemical staining (ICC) for ER, PR, and HER2 performed on formalin-fixed, paraffin-embedded cell blocks prepared from both FNA and serous effusion samples are reliable [3]. However, cell blocks sometimes lack adequate cellularity even when the direct smears are abundantly cellular. The cell transfer technique is a very useful method for obtaining cellular material for immunostaining and molecular testing if conventionally prepared cell blocks lack adequate cellularity [8, 14-19]. In our study 15% (24/163) of breast biomarker studies were performed on the cell-transferred smears that otherwise would not have been performed due to inadequate cellularity in the cell block. There are several advantages to using the cell transfer technique. It is technically simple and can be easily taught to and performed by a cytotechnologist or histotechnologist. No special equipment is required to perform the technique and the cost is relatively low. Furthermore, even if few diagnostic smears are available for a particular case, multiple immunostains can be performed from a single cellular smear. In addition to ER, PR, and HER2, we can perform GATA3 or mammaglobin ICC on a single cellular smear using the cell transfer technique to confirm the tumor origin from a breast primary. One important limitation to the use of CTT is that only ethanol-fixed direct smears can be used, as air-dried, methanol-fixed slides have previously been shown to have a false negative rate of approximately 30% and also often demonstrate nonspecific background staining [16].
Biomarker status of metastatic breast carcinoma can be reliably assessed by FNA and immunocytochemistry utilizing both cell block and cell transfer techniques. Our study demonstrates a successful rate of 94% (153/163) on providing the ICC results of ER, PR and HER2 on FNA specimens of metastatic/recurrent breast carcinoma.
Citation: Wu HH, Alderman M (2016) Hormone Receptor Assessment of Metastatic Breast Carcinoma by Fine Needle Aspiration Utilizing Cell Blocks and Cell Transfer Techniques: An Immunocytochemical Review of 163 Consecutive Cases. J Cytol Tissue Biol 3: 009.
Copyright: © 2016 Howard H Wu, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.