Prognostic significance of pleural fluid data in patients with malignant effusion

BackgroundTo determine the effects of the biochemical and cytological properties of the pleural fluid (PF) on the survival of patients with malignant pleural effusion (MPE).MethodsA retrospective study of 284 patients with MPE was performed, which measured overall survival, survival of patients with different types of primary tumors, and survival as a function of PF biochemical variables transformed into quartiles.ResultsMedian overall survival of MPE patients was 5.4 months following diagnosis. Survival varied significantly depending on the type of the primary tumor: 17.4 months for mesothelioma, 13.2 months for breast cancer, 7 months for lymphoma and 2.6 months for lung cancer. A multivariate analysis of PF biochemical parameters showed that survival was lower as the concentration of lactate dehydrogenase (LDH) increased (11.3 months if LDH was between 140 U/L and 358 U/L vs 2.8 months if LDH was between 1027 U/L and 10,110 U/L) or the concentration of pleural proteins decreased (9.4 months if proteins were between 4.92 g/dL and 7.94 g/dL vs 2.2 months if proteins were between 0.97 g/dL and 3.85 g/dL). We also found that when mesotheliomas were excluded from the analysis, survival was lower in patients with a PF pH lower than 7.3 (2.4 months vs 6.8 months, p = 0.03).ConclusionsTumor type as well as some biochemical features of the pleural fluid, such as pH and concentrations of proteins and LDH, influence survival in patients with MPE.