Fine-needle aspiration cytology as the first pathological diagnostic modality in breast lesions: A comparison with core needle biopsy

Background and aim: Breast cancer is the second most common malignancy in Korean women. Fine needle aspiration cytology (FNAC) has been used as the first-line pathological modality; however, use of core needle biopsy (CNB) is on the increase. FNAC is a cost effective, less invasive and rapid method for evaluation of breast lesions. The limitations of FNAC, such as high false negative rates and equivocal results restrict its use. The aim of this study is to evaluate FNAC as a diagnostic tool in comparison with CNB by matching corresponding excision specimens. Methods: From May, 2003 to April, 2008, 753 cases of FNAC, 331 cases of CNB, and 98 cases of combined FNAC and CNB were collected. Diagnoses with FNAC and CNB were compared with excision. Results: Sensitivity, specificity, and diagnostic accuracy of FNAC were 93.8%, 80.8%, and 90.1%, respectively. Those of CNB were 92.1%, 90.9%, and 92.3%, and combined FNAC and CNB, 100%, 77.8%, and 98.0%. There were no false positive cases in either the FNAC or the CNB group. False negative rates were 6.2% in FNAC and 9.9% in CNB. Sampling error was the cause of error or a false negative result in all FNAC samples, and all but one CNB sample. Diagnostic accuracy of FNAC was superior to that of CNB for lesions between 1 cm and 2 cm. Conclusions: Our data suggest that FNAC is an accurate and reliable first line diagnostic tool for evaluation of breast lesions when compared with core biopsy.