Prognostic Score of Long-Term Survival After Surgery for Malignant Pleural Mesothelioma: A Multicenter Analysis

Despite ongoing efforts to improve therapy in malignant pleural mesothelioma, few patients undergoing extrapleural pneumonectomy experience long-term survival (LTS). This study aims to explore predictors of LTS after extrapleural pneumonectomy and to define a prognostic score.

From January 2000 to December 2010, we retrospectively reviewed clinicopathologic and oncological factors in a multicenter cohort of 468 malignant pleural mesothelioma patients undergoing extrapleural pneumonectomy. LTS was defined as survival longer than 3 years. Associations were evaluated using χ(2), Student's t, and Mann-Whitney U tests. Logistic regression, Cox regression hazard model, and bootstrap analysis were applied to identify outcome predictors. Survival curves were calculated by the Kaplan-Meier method. Receiver operating characteristic analyses were used to estimate optimal cutoff and area under the curve for accuracy of the model.

Overall, 107 patients (22.9%) survived at least 3 years. Median overall, cancer-specific, and disease-free survival times were 60 (95% confidence interval [CI], 51 to 69), 63 (95% CI, 54 to 72), and 49 months (95% CI, 39 to 58), respectively. At multivariate analysis, age (odds ratio, 0.51; 95% CI, 0.31 to 0.82), epithelioid histology (odds ratio, 7.07; 95% CI, 1.56 to 31.93), no history of asbestos exposure (odds ratio, 3.13; 95% CI, 1.13 to 8.66), and the ratio between metastatic and resected lymph nodes less than 22% (odds ratio, 4.12; 95% CI, 1.68 to 10.12) were independent predictors of LTS. According to these factors, we created a scoring system for LTS that allowed us to correctly predict overall, cancer-specific, and disease-free survival in the total sample, obtaining two different groups with favorable or poor prognosis (area under the curve, 0.74; standard error, 0.04; p < 0.0001).

Our prognostic model facilitates the prediction of LTS after surgery for malignant pleural mesothelioma and can help to stratify the outcome and, eventually, tailor postoperative treatment.