Prognostic impact of inflammation in malignant pleural mesothelioma: A large-scale analysis of consecutive patients

Background: Prediction of prognosis is a key step of malignant pleural mesothelioma (MPM) management and treatment assignment. Aim of this study was to identify simple prognostic factors, focusing on inflammation-related parameters.

Methods: Baseline clinical and laboratory data were extracted from a single-center 20-year cohort of consecutive patients exhibiting a proven MPM. Inflammation-related ratios and composite scores were evaluated as prognostic indicators.

Results: 468 patients were identified. Mean age and BMI were 73.0 years and 25.1 kg/m². The histologic subtype was epithelioid, sarcomatoid, or biphasic in 80.3%, 6.2%, and 13.5% of cases, respectively. Mean Neutrophil to Lymphocyte Ratio (NLR), systemic Inflammation Index (SII) and Advanced Lung cancer inflammation Index (ALI) were 5.8, 1,836.6, and 29.6. Median survival was 13.0 months. Univariate analyses revealed that age > 70 years, persistent asthenia, hemoglobin < 13 g/dL, and non-epithelioid histologic type were associated with poorer survival, as well as the following high-inflammation-related criteria: CRP > 25 mg/L, white blood cell count (WBC) > 10⁹/dL, NLR > 5, SII > 1,270, and ALI < 18. Multivariate regression showed that age, histology, hemoglobin, and WBC were independent predictors of survival. Also, the inflammation-related factors ALI and NLR were independently associated with survival. Interestingly, hemoglobin was statistically significant predictor of survival in all multivariate models. We found higher proportion of survival > 18 months (66th percentile) in patients exhibiting SII < 2,000 and NLR < 5.

Conclusion: The prognosis of MPM is strongly influenced by systemic inflammation and patients exhibiting higher NLR, SII and lower ALI have shorter survival, which strengthens the level of evidence about the major role played by inflammation in MPM.