Pretreatment platelet level is associated with tumor proliferation and prognosis in malignant pleural mesothelioma.

Objective: The present study aimed to investigate the relationship between serum-based inflammatory biomarkers and MPM tumor biology and prognosis.

Methods: A total of 83 patients with MPM who were diagnosed and started treatment between January 1998 and December 2010 were studied. Clinicopathological variables were evaluated, including age, sex, clinical stage, histology, surgical resection, and chemotherapy. The cut-off values for pretreatment levels of white blood cell count, neutrophil count, lymphocyte count, platelet count, C-reactive protein, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index were determined using receiver operating characteristic curve analysis for predicting 5-year survival. Univariate and multivariate Cox regression analyses were performed to estimate the prognostic impact on 5-year overall survival.

Results: The mean Ki-67 proliferation index in MPM cells was 35.1 ± 29.5% and the median overall survival of patients was 15.0 months. The Ki-67 proliferation index in MPM cells was significantly higher in the platelet-high group compared with that in the platelet-low group (42.1 ± 31.9 vs. 27.7 ± 25.1%; P = 0.027). Multivariate Cox regression analyses identified platelet count (hazard ratio = 1.929; P = 0.022) and PLR (hazard ratio = 1.776; P = 0.040) as significant prognostic factors.

Conclusion: Pretreatment platelet level may be a useful prognostic marker for 5-year overall survival related to tumor proliferation in patients with MPM.