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 [CI] = 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% CI = 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% CI = 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.