Development of a Novel Prognostic Risk Classification System for Malignant Pleural Mesothelioma

The present study analyzed 188 patients with malignant pleural mesothelioma. Histologic type, lactate dehydrogenase, neutrophil-to-lymphocyte ratio, and total lesion glycolysis value were independent predictors. We developed a novel prognostic risk classification system. We believe that this prognostic risk classification system can reveal prognosis with a higher accuracy than the TNM classification. This prognostic system can be an essential noninvasive biomarker of malignant pleural mesothelioma. Introduction: This study aimed to assess prognostic factors to better understand malignant pleural mesothelioma (MPM) and to develop a new classification protocol beyond the standard tumor node metastasis (TNM) staging system. Materials and Methods: We retrospectively reviewed the data of 188 patients with MPM who had not undergone surgical resection. For each patient, we calculated the maximum standardized uptake value (SUVmax), metabolic tumor volume, and total lesion glycolysis (TLG) on pretreatment 18 F-fluoro-2-deoxyglucose-positron emission tomography/computed tomography. Using the Cox proportional hazards model, we evaluated the relationships among potential MPM predictors, including age, gender, performance status, histologic type, stage, possible serum markers, and volume-based positron emission tomography parameters, as well as overall survival. Results: The median survival was 461 days, and the 1- and 2-year overall survival rates were 60.70% and 31.10%, respectively. Univariate and multivariate analyses revealed that the significant independent predictors of poor survival outcomes were the nonepithelioid histologic type, elevated serum lactate dehydrogenase levels, a neutrophil-to-lymphocyte ratio of >= 5.0, and a TLG of >= 525 g. We then used these results to develop a prognostic risk classification system. From the resulting survival curve, we found a significant difference among the 3 risk groups of independent variables. Moreover, there were significant differences between all pairs of 2 separated risk groups. Conclusions: Pathologic subtypes, serum lactate dehydrogenase, neutrophil-to-lymphocyte ratio, and TLG in F-18-fluoro-2-deoxyglucose-positron emission tomography/computed tomography were independent and significant prognostic factors of MPM. Using this model, we created a new risk classification system that supplants the standard TNM staging protocol. (C) 2019 Elsevier Inc. All rights reserved.