Case-control study about magnitude of exposure to wood smoke and risk of developing lung cancer.

INTRODUCTION: Exposure to biomass combustion products, particularly firewood, has been considered as a potential carcinogen for developing lung cancer. In this regard, current evidence is widely heterogeneous; besides, in most studies, wood smoke exposure is not appropriately quantified, which further complicates the analysis of wood smoke as a potential carcinogen. The aim of the present study was to estimate the risk of developing lung cancer according to the degree of exposure to wood smoke in patients who use firewood for cooking. MATERIAL AND METHODS: We performed a case-control study that included 482 patients with lung cancer (cases) and 592 hospital controls. Exposure to wood smoke was evaluated as a dichotomous variable (i.e. yes or no); in patients with prior wood smoke exposure, an index of exposure in hours per year was calculated (WSEI). Using bivariate and multivariate logistic regression analyses, the odds ratio (OR) between wood smoke exposure and lung cancer were calculated. RESULTS: The ORs for developing lung cancer (raw and adjusted) for a WSEI > 100 h/year were OR 1.55 [95% confidence interval (CI), 1.06-2.26) and OR 2.26 (95% CI, 1.50-3.40), respectively; the ORs (raw and adjusted) for WSEI >300 h/year were OR 1.76 (95% CI, 1.06-2.91) and OR 3.19 (95% CI, 1.83-5.55), respectively. CONCLUSIONS: Exposure to wood smoke is a risk factor for lung cancer; furthermore, this effect maintains a dose-response relationship which has a multiplicative effect with smoking.

Accuracy of closed pleural biopsy in the diagnosis of malignant pleural effusion / Exactitud de la biopsia pleural cerrada para el diagnóstico de derrame pleural maligno

ABSTRACT Objective: Previous studies have demonstrated that closed pleural biopsy (CPB) has a sensitivity of less than 60% for diagnosing malignancy. Therefore, controversy has recently emerged regarding the value of CPB as a diagnostic test. Our objective was to assess the accuracy of CPB in diagnosing malignancy in patients with pleural effusion. Methods: This was a prospective 8-year study of individuals who underwent CPB to establish the etiology of pleural effusion. Information on each patient was obtained from anatomopathological reports and medical records. When CPB findings showed malignancy or tuberculosis, the biopsy was considered diagnostic, and that was the definitive diagnosis. In cases in which biopsy histopathological findings were nonspecific, a definitive diagnosis was established on the basis of other diagnostic procedures, such as thoracoscopy, thoracotomy, fiberoptic bronchoscopy, biochemical and cellular measurements in pleural fluid, and/or microbiological tests. The accuracy of CPB was determined with 2 × 2 contingency tables. Results: A total of 1034 biopsies from patients with pleural effusion were studied. Of those, 171 (16.54%) were excluded from the accuracy analysis either because of inadequate samples or insufficient information. The results of the accuracy analysis were as follows: sensitivity, 77%; specificity, 98%; positive predictive value, 99%; negative predictive value, 66%; positive likelihood ratio, 38.5; negative likelihood ratio, 0.23; pre-test probability, 2.13; and post-test probability, 82. Conclusions: CPB is useful in clinical practice as a diagnostic test, because there is an important change from pre-test to post-test probability.

RESUMEN Objetivo: Estudios previos demuestran que la biopsia pleural cerrada (BPC) para diagnóstico de malignidad tiene una sensibilidad menor al 60%, por lo que recientemente ha despertado controversia su valor como prueba diagnóstica. Nuestro objetivo fue evaluar la exactitud de la BPC para diagnóstico de malignidad en pacientes con derrame pleural. Métodos: Estudio prospectivo de 8 años en individuos que se sometieron a la realización de BPC para establecer la etiología del derrame. La información de cada paciente se tomó de los registros de anatomopatología y del expediente clínico. Cuando el resultado de la BPC demostró malignidad o tuberculosis, esto se tomó como biopsia diagnóstica y quedó éste como diagnóstico definitivo. En los casos en que el resultado del estudio histopatológico de la biopsia resultó inespecífico, el diagnóstico definitivo se estableció en base a otros procedimientos diagnósticos, como toracoscopia, toracotomía, fibrobroncoscopia, estudio bioquímico y celular del líquido pleural y/o pruebas microbiológicas. Mediante una tabla de contingencia de 2 × 2 se midieron los indicadores para una prueba diagnóstica. Resultados: Se estudiaron 1034 biopsias de pacientes con derrame pleural, de las cuales se excluyeron 171 (16.54%) por muestra inadecuada o información insuficiente. El desempeño para malignidad fue: sensibilidad, 77%; especificidad, 98%; valores predictivos positivo y negativo, 99% y 66%, respectivamente; índices de probabilidad positivo y negativo, 38.5 y 0.23, respectivamente; probabilidad antes y después de la prueba, 2.13 y 82, respectivamente. Conclusión: La BPC es útil como prueba diagnóstica en la práctica clínica, debido a que produce un cambio importante de la probabilidad antes de la prueba a la probabilidad después de la prueba.

Accuracy of closed pleural biopsy in the diagnosis of malignant pleural effusion.

OBJECTIVE: Previous studies have demonstrated that closed pleural biopsy (CPB) has a sensitivity of less than 60% for diagnosing malignancy. Therefore, controversy has recently emerged regarding the value of CPB as a diagnostic test. Our objective was to assess the accuracy of CPB in diagnosing malignancy in patients with pleural effusion. METHODS: This was a prospective 8-year study of individuals who underwent CPB to establish the etiology of pleural effusion. Information on each patient was obtained from anatomopathological reports and medical records. When CPB findings showed malignancy or tuberculosis, the biopsy was considered diagnostic, and that was the definitive diagnosis. In cases in which biopsy histopathological findings were nonspecific, a definitive diagnosis was established on the basis of other diagnostic procedures, such as thoracoscopy, thoracotomy, fiberoptic bronchoscopy, biochemical and cellular measurements in pleural fluid, and/or microbiological tests. The accuracy of CPB was determined with 2 × 2 contingency tables. RESULTS: A total of 1034 biopsies from patients with pleural effusion were studied. Of those, 171 (16.54%) were excluded from the accuracy analysis either because of inadequate samples or insufficient information. The results of the accuracy analysis were as follows: sensitivity, 77%; specificity, 98%; positive predictive value, 99%; negative predictive value, 66%; positive likelihood ratio, 38.5; negative likelihood ratio, 0.23; pre-test probability, 2.13; and post-test probability, 82. CONCLUSIONS: CPB is useful in clinical practice as a diagnostic test, because there is an important change from pre-test to post-test probability.