Clinical Features in Patients With Malignant Pleural Mesothelioma With 5-Year Survival and Evaluation of Original Diagnoses

Abstract

Introduction: Malignant pleural mesothelioma (MPM) is a fatal malignancy strongly associated with previous asbestos exposure. Overall survival remains dismal, partly owing to poor response to available treatment. The aims of this study were to evaluate diagnostic accuracy in a group of patients with MPM with an unusually long survival time and to assess the factors related to this prolonged survival.

Materials and methods: Forty-three patients with overall survival exceeding 5 years were accepted to the long-term survivor (LTS) group, and these patients were compared with 84 patients with epithelial MPM. Data were collected from various national registries and electronic medical records. In addition, all available histopathologic diagnostic samples and computed tomography studies were re-evaluated by experienced specialists.

Results: Our study showed a good diagnostic accuracy, with only 1 (0.5%) patient having an incorrect MPM diagnosis. Two (0.9%) localized malignant mesotheliomas and 2 (0.9%) well-differentiated papillary mesotheliomas were also found. LTS patients were younger, more frequently female, had a better performance status at time of diagnosis, and had less evidence of prior asbestos exposure. In multivariate analysis, we showed tumor size, Eastern Cooperative Oncology Group performance status, and first-line treatment (both surgery and chemotherapy) to be associated with survival time.

Conclusion: We confirmed the diagnosis of MPM in an overwhelming majority of patients in the LTS group. An epithelial subtype of MPM behaving clinically more indolently seems to exist, but further tumor and genetic characterization is needed. The prolonged survival time is most likely explained by a combination of tumor-, patient-, and treatment-related factors.

Keywords: Clinical factors; Diagnostic assessment; Long-term survivors; Prognostic factors; Survival time.