Cambios en los parámetros bioquímicos del líquido pleural entre 2 toracocentesis consecutivas para diferenciar derrames malignos de benignos / Detection of Pleural Fluid Biochemistry Changes in Two Consecutive Thoracenteses for Differentiating Malignant from Benign Effusions

Objetivo: Evaluar si los cambios en los parámetros bioquímicos del líquido pleural (LP) entre 2 toracocentesis sucesivas permiten predecir derrames pleurales (DP) malignos o benignos. Métodos: Estudio retrospectivo de los pacientes con exudado linfocitario y citología negativa para malignidad que se sometieron a una segunda toracocentesis en nuestro centro durante los últimos 15 años (muestra de derivación), y en los que se alcanzó un diagnóstico final. Las diferencias absolutas (Δa) o porcentuales (Δp) de diferentes parámetros bioquímicos del LP capaces de predecir la naturaleza maligna o benigna del DP en la muestra de derivación se evaluaron en una población independiente. Resultados: Se incluyeron 214 pacientes con DP (70 malignos y 144 benignos) en la muestra de derivación. Las Δp LDH (lactato deshidrogenasa) > 0%, Δp neutrófilos > -10% (cualquier aumento o bien un descenso inferior al 10%), y Δa proteínas < 0,1 g/dL (cualquier descenso o bien un aumento inferior a 0,1 g/dL) entre la segunda y primera toracocentesis mostraron unas odds ratio de 6,4, 3,9 y 2,1 para discriminar DP maligno de benigno, respectivamente. La presencia de las 3 condiciones conjuntamente se asoció con una likelihood ratio positiva de 5,6, mientras que la ausencia de cualquiera ellas se asoció con una likelihood ratio negativa de 0,04 para predecir malignidad. Los resultados se reprodujeron en la población de validación. Conclusión: El aumento de LDH y neutrófilos, junto con el descenso de proteínas en una segunda toracocentesis, aumenta la probabilidad de que el origen del DP sea neoplásico, mientras que lo contrario la reduce significativamente

Objective: To assess whether changes in pleural fluid (PF) biochemistries between two consecutive thoracenteses enable clinicians to predict malignant or benign pleural effusions (PE). Methods: Retrospective study of patients with lymphocytic exudates and negative PF cytology, who underwent a second thoracentesis in our center in the last 15 years in whom a final diagnosis was reached (derivation sample). Absolute (Δa) and percentage differences (Δp) in PF biochemistries which predicted a malignant or benign PE in the derivation sample were evaluated in an independent population (validation sample). Results: The derivation sample included 214 PE patients (70 malignant and 144 benign PE). Δp lactate dehydrogenase (LDH) >0%, Δp neutrophils >-10% (any increase or less than 10% decrease) and Δa protein <0.1g/dL (any increase or less than 0.1g/dL decrease) between the second and the first thoracentesis had an odds ratio of 6.4, 3.9 and 2.1, respectively, to discriminate malignant from benign PE. The presence of the three conditions together had a positive likelihood ratio of 5.6, whereas the absence of any of the 3 parameters had a likelihood ratio of 0.04 for predicting malignancy. These results were reproduced in the validation sample. Conclusion: An increase in LDH and neutrophils along with a decrease in protein in a second thoracentesis increase the probability of malignant PE, while the opposite reduces it significantly

Detection of Pleural Fluid Biochemistry Changes in Two Consecutive Thoracenteses for Differentiating Malignant from Benign Effusions. / Cambios en los parámetros bioquímicos del líquido pleural entre 2 toracocentesis consecutivas para diferenciar derrames malignos de benignos.

OBJECTIVE: To assess whether changes in pleural fluid (PF) biochemistries between two consecutive thoracenteses enable clinicians to predict malignant or benign pleural effusions (PE). METHODS: Retrospective study of patients with lymphocytic exudates and negative PF cytology, who underwent a second thoracentesis in our center in the last 15 years in whom a final diagnosis was reached (derivation sample). Absolute (Δa) and percentage differences (Δp) in PF biochemistries which predicted a malignant or benign PE in the derivation sample were evaluated in an independent population (validation sample). RESULTS: The derivation sample included 214 PE patients (70 malignant and 144 benign PE). Δp lactate dehydrogenase (LDH) >0%, Δp neutrophils >-10% (any increase or less than 10% decrease) and Δa protein <0.1g/dL (any increase or less than 0.1g/dL decrease) between the second and the first thoracentesis had an odds ratio of 6.4, 3.9 and 2.1, respectively, to discriminate malignant from benign PE. The presence of the three conditions together had a positive likelihood ratio of 5.6, whereas the absence of any of the 3 parameters had a likelihood ratio of 0.04 for predicting malignancy. These results were reproduced in the validation sample. CONCLUSION: An increase in LDH and neutrophils along with a decrease in protein in a second thoracentesis increase the probability of malignant PE, while the opposite reduces it significantly.