Breast fine needle aspiration continues to be relevant in a large academic medical center: experience from Massachusetts General Hospital.

Fine needle aspiration (FNA) is increasingly being supplanted by core needle biopsy. However, breast surgeons continue to rely on FNA at our institution. This retrospective study evaluated breast FNA for its diagnostic accuracy and breast cancer biomarker testing utility. All breast FNAs performed at Massachusetts General Hospital 2009-2015 were reviewed. Cytology diagnoses were compared with subsequent tissue or clinical diagnoses. Immunohistochemistry and fluorescence in situ hybridization (FISH) results using formalin-fixed paraffin-embedded (FFPE) cell blocks and histologic tissue blocks were compared. 1654 consecutive breast FNAs were included. Breast FNA demonstrated the following diagnostic performance: positive predictive value of malignant cytology diagnosis 100 %, negative predictive value of benign cytology diagnosis 97.5 %, complete sensitivity 91.6 %, and specificity 95.5 %. Concordance rates for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) immunohistochemistry, and HER2 FISH were 98.2 % (κ = 0.95, p < 0.001), 100.0 % (κ = 1.000, p < 0.001), 83.1 % (κ = 0.69, p < 0.001), and 93.5 % (κ = 0.785, p < 0.001), respectively. Review of consecutive breast FNAs in a large cohort confirmed the excellent accuracy of this biopsy technique for breast lesion diagnosis. FNA FFPE cell blocks collected in the course of routine clinical care are adequate, practical, and reliable for breast cancer biomarker testing.