Contemporary Analysis of Prognostic Factors in Patients with Unresectable Malignant Pleural Mesothelioma

IntroductionPrevious prognostic scoring systems for malignant pleural mesothelioma (MPM) included patients managed surgically and predated the use of pemetrexed. We analyzed prognostic factors in a contemporary cohort of patients with unresectable MPM who received pemetrexed-based chemotherapy.MethodsThis single-institution analysis included patients with MPM who were managed nonsurgically from 2000 to 2013. Variables correlated with overall survival (OS) included sex, performance status (PS), asbestos exposure, tumor laterality, histology, clinical stage, initial positron emission tomography maximum standardized uptake value, hemoglobin level, platelet count, lymphocyte count, white cell and neutrophil counts, treatment type, and clinical benefit from treatment. OS was analyzed by the Kaplan-Meier method, and significance (p < 0.05) of prognostic factors was analyzed by the log-rank test and Cox regression.ResultsA total of 191 patients met the study criteria: median age 71 years (range 46–90), 147 men (77%), 128 epithelioid tumors (67%), and 157 cases of stage III or IV MPM (82%). Median OS for all patients was 13.4 months. According to a univariate analysis, histology (p < 0.001), platelet count (≤450,000 versus >450,000, p < 0.001), initial PS (0–1 versus ≥2), maximum standardized uptake value (≤8.1 versus >8.1, p = 0.037), and lymphocyte counts (p = 0.019) were associated with OS. According to a multivariable analysis, only histology, platelet count, and PS were independent prognostic factors. Epithelioid histology, PS, and elevated lymphocyte count at diagnosis were significantly associated with clinical benefit from first-line chemotherapy.ConclusionsOur results confirm the significance of elements of the Cancer and Leukemia Group B and European Organisation for Research and Treatment of Cancer prognostic scoring systems, identify factors associated with clinical benefit from chemotherapy, and emphasize the impact of histology and clinical benefit of chemotherapy on outcomes.