Supplementary Material for: Systematic Review and Meta-Analysis of the Diagnostic Accuracy of the Sydney System for Reporting Lymph Node Fine-Needle Aspiration Biopsy in Diagnosing Malignancy

Introduction To perform the first meta-analysis for assessment of the pooled risk of malignancy of each category of the Sydney system for reporting of lymph nodal aspirates along with evaluation of diagnostic accuracy. Methods Pubmed/ MEDLINE and Embase were searched with the following keywords “(Lymph node) AND ("fine needle aspiration biopsy" OR FNAB) OR (International system OR Sydney system)” in the timeframe 2020 to August 04, 2023. The selected articles were assessed for risk of bias by the QUADAS-2 tool. The meta-analysis for sensitivity and specificity for each cut-off, that is, “Atypical considered positive,” “Suspicious of Malignancy considered positive,” and “Malignant considered positive” for the lesions was carried out after excluding the inadequate samples in each study. To assess the diagnostic accuracy, summary receiver operating characteristic (sROC) curves were constructed, and the diagnostic odds ratio (DOR) was pooled in both scenarios. Results Nine studies, all of which were retrospective cross-sectional studies were evaluated with a total of 13205 cases. The sensitivity and specificity for the “Atypical and higher risk categories” considered as positive for malignancy were 97% (95% CI, 95%-99%), and 96% (95% CI, 91%-98%) respectively. The sensitivity and specificity for the “Suspicious for malignancy and higher risk categories” considered as positive for malignancy were 91% (95% CI, 85%-95%), and 99% (95% CI, 97%-100%) respectively. The sensitivity and specificity for the “Malignant” considered as positive for malignancy were 75% (95% CI, 65%-84%), and 100% (95% CI, 99%-100%) respectively. The pooled Area under the curve was 99-100% for each of the cut-offs. Conclusion This meta-analysis highlights the accuracy of the Sydney system in reporting lymph node aspirates. It exhibits the significance of the “Suspicious” and “Malignant” categories in diagnosing malignancy and of the “ Benign” category in excluding malignancy.引言 本研究首次开展荟萃分析，旨在评估用于报告淋巴结抽吸物的悉尼系统（Sydney system）各分类的恶性肿瘤合并风险，并评价其诊断准确性。方法 于2020年至2023年8月4日期间，以"(淋巴结) AND ("细针抽吸活检" OR FNAB) OR (国际分类系统 OR 悉尼系统)"为检索式检索PubMed/MEDLINE及Embase数据库。采用QUADAS-2工具对纳入文献进行偏倚风险评价。在排除各项研究中不合格样本后，针对"非典型性视为阳性""疑似恶性视为阳性""恶性视为阳性"这三个截断值，分别开展各截断值的灵敏度与特异度荟萃分析。为评价诊断准确性，构建汇总受试者工作特征（summary receiver operating characteristic, sROC）曲线，并对相关分析场景下的诊断优势比（diagnostic odds ratio, DOR）进行合并分析。结果 共纳入9项回顾性横断面研究，累计纳入13205例病例。将"非典型性及更高风险类别"视为恶性阳性时，其灵敏度为97%（95%CI：95%~99%），特异度为96%（95%CI：91%~98%）。将"疑似恶性及更高风险类别"视为恶性阳性时，其灵敏度为91%（95%CI：85%~95%），特异度为99%（95%CI：97%~100%）。将"恶性"视为恶性阳性时，其灵敏度为75%（95%CI：65%~84%），特异度为100%（95%CI：99%~100%）。各截断值的汇总曲线下面积均为99%~100%。结论 本荟萃分析证实了悉尼系统在淋巴结抽吸物报告中的应用准确性，明确了"疑似"与"恶性"类别在恶性肿瘤诊断中的意义，以及"良性"类别在排除恶性肿瘤中的价值。