[367] FNA Evaluation of Axillary Lymph Nodes for Breast Cancer Strongly Correlates with Surgical Pathology

Adele Fung, Paul N Staats. University of Maryland Medical Center, Baltimore, MD

Background: Breast carcinoma is the most common malignancy and the leading cause of death for women in the United States. Axillary lymph node status is the most important prognostic factor. Pre-operative assessment of lymph node status by fine needle aspiration (FNA) is increasingly desired for assessment of lymph node status prior to neoadjuvant therapy. Moreover, surgical excision of axillary lymph nodes has sequela, including lymphedema, pain, shoulder restriction, numbness and weakness. However, there is limited literature assessing the correlation of FNA results with surgical excision.
Design: A search of the pathology database from 1/07 to 9/12 for cytology cases with keyword axilla was conducted. Two hundred and forty cases, where patients had a history of a breast mass or breast carcinoma and an axillary lymph node fine needle aspiration, were identified. One hundred thirty eight cases had follow-up core biopsy, sentinel node biopsy, or axillary dissection. Correlation was calculated using the Goodman-Kruskal Gamma. Cases with discordant results were reviewed by the authors to determine the cause of the discrepancy.
Results: Of the 138 cases, 132 (96%) were definitively positive or negative on cytology; 109 (83%) were concordant with the surgical result (Goodman-Kruskal Gamma = 0.84). Of the 23 discrepant cases, 5 were positive on cytology but negative on surgical excision; all of these patients had neoadjuvant therapy, and the cases are interpreted as true positives with interval complete tumor response. The other 18 cases were negative on cytology but positive on surgical excision; 2 were called isolated tumor cells or micrometastasis, and the rest had partial involvement of the lymph node by a small volume of tumor, and were classified as cytology sampling error. The 6 cases for which a definitive diagnosis could not be rendered were also due to insufficient cytology sampling: 3 were called atypical due to very rare abnormal cells, with 2 positive and 1 negative on surgical excision. Three cases were non-diagnostic on cytology due to lack of lymph node sampling. Overall, the positive predictive value of axillary FNA was 100% and the negative predictive value was 78%.
Conclusions: FNA cytology of axillary lymph nodes is strongly correlated with surgical pathology diagnosis, with 78% NPV, 100% PPV and a very low non-diagnostic rate. All discrepancies appear to be due to sampling error during FNA, mostly in lymph nodes with small tumor burden. The findings support the role of pre-treatment FNA evaluation of axillary lymph node status in patients with breast carcinoma.
Category: Cytopathology

Tuesday, March 5, 2013 11:45 AM

Proffered Papers: Section F, Tuesday Morning


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