Differential diagnostic CYFRA 21-1 level for benign and malignant pleural effusions: a meta-analysis in the Chinese population

Introduction: Many studies have investigated the usefulness of cytokeratin 19 fragments (CYFRA 21-1) in pleural fluid for the differential diagnosis of benign (BPE) and malignant pleural (MPE) effusions. In the present meta-analysis, the reported studies on the diagnosis between CYFRA 21-1 and pleural effusion were assessed to summarize the diagnostic characteristics of CYFRA 21-1 in Chinese patients. Material and methods: The data sources from the creation of each database up to January 2011 included Medline, Chinese National Knowledge Infrastructure, EMBASE, Cochrane library, and bibliographies of review and original articles. Through a systematic literature search for publications, the data from 22 studies were summarized based on their discussions on the result of the CYFRA 21-1 assay in pleural effusion and differential diagnosis evaluation in the Chinese population. Results: A total of 22 studies were available for analysis, and the high CYFRA 21-1 level in MPE was significantly associated with risk for lung cancer (standardized mean difference [SMD] = 1.65, 95% confidence interval [Cl] = 1.48-1.82, Z = 18.97, p < 0.00001) compared with BPE. The CYFRA 21-1 level in pleural effusion (13 studies) was significantly higher than that in serum (SMD = 1.10, 95% Cl = 0.71-1.48, Z = 5.59, p < 0.00001). The risk for squamous cell carcinoma (SCC) for CYFRA 21-1 was 1.03 (95% Cl = 0.64-1.42, Z = 5.15, p < 0.00001) compared with that of adenocarcinoma (8 studies). The sensitivity of CYFRA 21-1 reported in the articles ranged from 46% to 94%, and the specificity ranged from 57% to 100%. The summary measure of the test characteristics derived from the summary receiver operating characteristic curve was 81% for both sensitivity and specificity (17 studies). Conclusions: The measurement of pleural CYFRA 21-1 is likely to be a useful diagnostic tool for the confirmation of MPE.