Diagnostic accuracy of pleural fluid carbohydrate antigen 72-4 for malignant pleural effusion: a systematic review and meta-analysis

Background: Several studies have evaluated the diagnostic accuracy of pleural fluid carbohydrate antigen 72-4 (CA72-4) for malignant pleural effusion (MPE), but the results were diverse. This systematic review and meta-analysis aimed to evaluate the diagnostic accuracy of pleural fluid CA72-4 for MPE. Methods: The PubMed and Web of Science databases were searched to verify potential studies investigating the diagnostic accuracy of pleural fluid CA72-4 for MPE. The last search date was August 2024. The quality of the eligible studies was assessed by this study using the revised diagnostic accuracy study quality assessment tool-2 to assess the quality of the eligible studies. This study used a summary receiver operating characteristic (sROC) curve and a bivariate model to pool the findings and their 95% confidence intervals (CIs) of available studies. Results: Eight studies with 828 cases of MPEs and 963 cases of benign pleural effusion (BPE) were included in the present meta-analysis. The pooled sensitivity (95% CI) and specificity (95% CI) were 0.47 (0.39-0.55) and 0.98 (0.95-0.99). The area under sROC curves was 0.77 (95% CI: 0.73-0.80). The primary design weaknesses of the included studies were the representativeness of the participants and the data-driven threshold to define positive CA72-4. A significant publication bias was observed across the eligible studies. Conclusions: Pleural fluid CA72-4 is an auxiliary diagnostic marker for MPE. However, its diagnostic accuracy may be overestimated by available studies.