Accuracy of ultrasound-guided vacuum-assisted fineneedle aspiration for diagnosis and management of BI-RADS 4 lesion

Abstract

Background: Breast imaging-reporting and data system (BI-RADS) 4 lesion is in the category of suspicion for
malignancy which has to be managed with core needle biopsy as specified in the standard guideline. Nonetheless,
at King Chulalongkorn Memorial Hospital, an ultrasound-guided vacuum-assisted fine-needle aspiration (FNA)
is performed in some cases of BI-RADS 4 lesion because it has been considered a simple and cost-effective tool
for managing breast lesion in previous study.

Objectives: This study aimed to evaluate the accuracy of an ultrasound-guided vacuum-assisted fine-needle
aspiration in the diagnosis and management of BI-RADS 4 lesion.

Methods: A retrospective review was conducted on 251 female patients with BI-RADS 4 lesion who underwent
an ultrasound-guided vacuum-assisted FNA, together with a subsequent procedure of either surgical biopsy or
follow-up imaging for at least 2 years at King Chulalongkorn Memorial Hospital from January 2011 to December
2013. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the study
data were evaluated. Also, the underestimation rate of unsatisfactory samples (C1) was calculated.

Results: The sensitivity, specificity, PPV and NPV for ultrasound-guided vacuum-assisted FNA were 72.73%
(95%CI: 67.22 - 78.24%), 98.07% (95%CI: 96.36 - 99.77%), 88.89% (95%CI: 85.0 - 92.78%) and 94.42% (95%CI:
91.58 - 97.26%) respectively. Sixteen patients with discordant lesions between FNA cytology and surgical
pathology were found; 4 of them (1.9%) were false positives and 12 (27.3%) were false negatives. Among
71 patients with unsatisfactory samples (C1), 67 cases (94.4%) showed benign results, while 4 cases (5.6%)
showed malignant results.

Conclusion: An ultrasound-guided vacuum-assisted FNA is a reliable diagnostic tool for BI-RADS 4 lesion.
However, there are some limitations that may cause false negative, especially in the case of a very small lesion,
an inexperienced performer along with other uncontrollable factors e.g. heterogeneity type of a tumor. Therefore,
subjects should be properly selected to prevent an error.