A comparison of aspiration cytology and core needle biopsy in the evaluation of breast lesions.

BACKGROUND: Several arguments are used for choosing either fine-needle aspiration cytology (FNAC) or core needle biopsy (CNB) in the evaluation of breast lesions. Comparison of published data on both methods is complicated by differences in study design, calculations, and operator experience. The objective of this study was to make a direct comparison of both methods. METHODS: In 286 breast lesions (cysts and microcalcifications without a soft tissue mass excluded), both ultrasound-guided FNAC and CNB were performed in the same session by the same operator. Histologic follow-up was collected, and for those lesions that were not excised the results of the most recent mammography was used. A combination of the findings of both FNAC and CNB were evaluated. RESULTS: Core needle biopsy and FNAC do equally well for sensitivity (88% vs. 92%), positive predictive value for malignancy (99% vs. 100%), and inadequate rate (7% vs. 7%). However, statistical differences are found for the specificity (CNB, 90%; FNAC, 82%). In addition, differences are found in the positive predictive value of both suspicious (CNB, 100%; FNAC, 78%) and atypia (CNB, 80%; FNAC, 18%) and for the suspicious rate (CNB, 5%; FNAC, 13%) reflecting difficulties in interpreting some FNACs. Combining the findings of both FNAC and CNB results in an increase in absolute sensitivity, a decrease in the positive predictive value of atypia compared with FNAC and CNB per se, and a decrease in the inadequate rate for cancers. CONCLUSIONS: For the lesions selected in this study, FNAC and CNB are comparable for most parameters, but CNB has a higher specificity and lower suspicious rate. Combining results of FNAC and CNB leads to an increase in absolute sensitivity without affecting specificity and a decrease in the inadequate rate for cancers.