<![CDATA[Background: Recurrent malignant pleural effusion (MPE) remains a significant clinical problem that often necessitates repeated interventions and negatively affects patients' quality of life. This study evaluated the association of pleural fluid glucose, pleural fluid CYFRA 21-1, and radiographic pleural effusion size with recurrent malignant pleural effusion. Methods: A single-center observational analytic study was conducted in 60 patients with malignant pleural effusion. Patients were classified into recurrent and non-recurrent groups based on pleural fluid reaccumulation requiring repeat thoracentesis within 30 days. Pleural glucose and CYFRA 21-1 levels were measured using enzyme-linked immunosorbent assay. One radiologist and one pulmonologist independently interpreted chest radiographs. Pleural effusion size was categorized according to the hilar level. Statistical analyses included the Chi-square test, Mann–Whitney U test, and receiver operating characteristic (ROC) curve analysis. Results: Recurrent pleural effusion occurred in 55% of patients. Effusion extending above the hilar level was observed in all recurrent cases and was significantly associated with recurrence (P<0.001). Patients with recurrent pleural effusion had significantly lower pleural glucose levels (39.53 vs 107.46 mg/dL; P<0.001) and higher pleural CYFRA 21-1 levels (58.61 vs 27.26 ng/mL; P<0.001) than those in the non-recurrent group. ROC analysis demonstrated excellent discriminative performance for pleural glucose (AUC=0.905) and pleural CYFRA 21-1 (AUC=0.933), with optimal cut-off values of <85.85 mg/dL and ≥44.02 ng/mL, respectively. Chest pain was the only clinical symptom significantly associated with recurrent pleural effusion (P<0.001). Conclusion: Lower pleural glucose levels, higher pleural CYFRA 21-1 levels, and radiographic pleural effusion extending above the hilar level were significantly associated with recurrent malignant pleural effusion. These parameters may serve as useful clinical markers to complement the evaluation of patients with recurrent MPE.]]>
