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

Methods: A retrospective review was conducted on 251 female patients with BI-RADS 4 lesions 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 lesions. However, there are some limitations that may cause false negatives, especially in the case of a very small lesions, such as an inexperienced performer along with other uncontrollable factors e.g. the heterogeneity type of a tumor. Therefore, subjects should be properly selected to prevent an error.