To investigate the accuracy of fine needle aspiration cytology (FNAC) in breast mass screening and breast cancer classification.

Based on the inclusion and exclusion criteria, 279 patients with breast mass undergoing FNAC and histopathological examination in the Department of Pathology, the First Affiliated Hospital of Tsinghua University from February 2015 to February 2017 were enrolled for a retrospective study. The results in FNAC and histopathological examination were compared . The Kappa value was used to evaluate the consistency of FNAC with histopathological examination in breast mass screening and classification. The area under the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of FNAC.

In 279 patients, the accuracy of FNAC was 90.3%(127/132) in breast lesions. For breast lesions, the diagnostic sensitivity of FNAC was 85.0% (125/147), specificity 96.2% (127/132), false positive rate 3.8% (5/132), false negative rate 15.0% (22/147), positive likelihood ratio 22.4, negative likelihood ratio 0.2. The consistency test of FNAC and histopathology showed that the Kappa value was 0.81 (P<0.001). The area under ROC curve was 0.95 (P<0.001) for FNAC diagnosis. Totally 125 patients were diagnosed as malignant breast tumor by FNAC and histopathology. In those 125 breast cancer patients, the consistency test of the two methods for classification showed that the Kappa value was 0.68 (P<0.001).

FNAC can be used as a good screening method for breast mass and it can provide guidance for preoperative classification of breast cancer and clinical treatment.