Validation of Prognostic Factors in Malignant Pleural Mesothelioma: A Retrospective Analysis of Data from Patients Seeking Compensation from the New South Wales Dust Diseases Board

Despite the generally poor prognosis, survival of individual patients with malignant pleural mesothelioma is quite variable. We investigated the prognostic significance of clinicopathologic factors and inflammatory markers in 148 patients with malignant pleural mesothelioma. Apart from previously recognized factors, such as histologic subtype, tumor stage, and hemoglobin level difference, blood neutrophil-to-lymphocyte ratio, an index of systemic inflammation, at the time of diagnosis bears prognostic significance independent of chemotherapy treatment effect, which showed that a snapshot of immune status is able to convey important prognostic information. Introduction: We aimed to examine the prognostic values of established risk factors and to validate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in an independent series of patients with malignant pleural mesothelioma (MPM). Patients and Methods: A total of 148 patients who applied for compensation at the Dust Diseases Board from 2007 to 2009 were included in this study. Overall survival was determined by the Kaplan-Meier method, and NLR was defined as the absolute neutrophil divided by the lymphocyte count. The prognostic value of the variables was examined by using Cox regression analysis, and all factors were entered into a multivariate model to determine their independent effect. Results: The patient characteristics were median age of 73 years; 93% men; 59% epithelial subtype; median NLR of 3.5 at diagnosis (n = 79); median overall survival of 10.6 months. The following variables were predictive of longer overall survival in univariate analysis: younger age, epithelial subtype, lower tumor stage, low white cell count, low platelet count, low hemoglobin level, and low NLR. Multivariate analysis confirmed that nonepithelial vs. epithelial subtype (hazard ratio [HR], 3.0; P < .001), tumor stage (HR, 1.6; P < .001), hemoglobin level difference >= 10 vs. <10 (HR, 2.0; P = .03), no chemotherapy vs. use of chemotherapy (HR, 2.4; P < .001), and NLR >= 3 vs. <3 (HR, 2.2; P < .01) were independently associated with prognosis. Conclusions: Apart from previously recognized factors, such as histosubtype, tumor stage, and hemoglobin level difference, NLR, an index of systemic inflammation bears prognostic significance that shows that a snapshot of immune status is able to convey important prognostic information. Clinical Lung Cancer, Vol. 14, No. 1, 70-7 (C) 2013 Elsevier Inc. All rights reserved.