Systematic Review and Meta-Analysis of the Diagnostic Accuracy of the International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy in Diagnosing Breast Cancer

Objectives: The primary objective is to determine the accuracy of fine-needle aspiration biopsy (FNAB) in breast lesions reported according to the International Academy of Cytology (IAC) Yokohama system for reporting breast FNAB. The participants include any patient presenting with any breast lesion found suitable for FNAB. The target condition was breast cancer. The secondary objective was to study the proportion of inadequate FNAB in the selected studies. Methods: PubMed/MEDLINE and Embase were searched for studies having all the following key search terms: Breast AND FNAB AND Diagnostic Accuracy published in the time frame of 2017 to May 16, 2022. The Cochrane and PROSPERO databases, citations of selected articles and articles citing the selected articles were also searched. Studies assessing the diagnostic accuracy of breast FNAB in diagnosing breast cancer, which had at least 75 subjects (and at least 20 subjects each in the benign and malignant FNAB groups), were selected. The reference standard was histopathology (or adequate clinical follow-up for benign disease). Studies were screened independently by two researchers, with a consensus reached among the authors in cases of conflict. The risk of bias and applicability were assessed using the QUADAS-2 tool. Sensitivity and specificity at each diagnostic cut-off were assessed by bivariate generalized linear mixed-model meta-analysis. The area under the receiver operating characteristics curve (AUC) and inadequacy rate were assessed by random-effects meta-analysis. The confidence intervals of sensitivity, specificity, and AUC were examined against a value of 0.95. Results: Twenty-two studies, all of which were cross-sectional single-gate studies, were selected with a total of 10,886 subjects with a primary breast lesion having concurrent FNAB and reference standard reports. Sensitivity and specificity, with 95% confidence intervals, were 0.978 [0.968, 0.985] and 0.832 [0.76, 0.886] for the diagnostic cut-off of "Atypical considered positive for malignancy, " 0.916 [0.892, 0.935] and 0.983 [0.97, 0.99] for the cut-off of "Suspicious of Malignancy considered positive, " and 0.763 [0.706, 0.812] and 0.999 [0.994, 1] for the cut-off of "Malignant considered positive. " The overall AUC was 0.975 [0.962, 0.984]. FNAB sampling without imaging guidance was associated with lower inadequacy. Discussion: There is strong evidence that the overall accuracy, sensitivity for "Atypical category considered positive " and specificity when "Suspicious or Malignant categories are considered positive " of FNAB are high when using the categories of the IAC Yokohama Reporting System, demonstrating the usefulness of FNAB in diagnosing breast cancer.