A new prognostic score in patients with malignant pleural mesothelioma.

Background: Available prognostic scores in malignant pleural mesothelioma (MPM) are based on multiple variables with conflicting results. The aims of the study were to identify prognostic factors for survival and create a new prognostic score including macroscopic features of pleural surfaces in patients with MPM. Methods: Retrospective study of 455 consecutive patients (307 men, 67.5%; 148 women, 32.5%; median age 66; range 28-93) with histologically proven MPM who underwent diagnostic thoracoscopy or open pleural biopsy between January 1990 and December 2007. Patients received either chemotherapy or best supportive care. All patients were followed up until death or for a minimum period of 2 years. Kaplan-Meier method, log-rank test, Cox model, and maximum-likelihood parameter estimates were used in the statistical analysis. Results: As of December 2009, 439 patients (96.5%) had died (median survival [MS], 11.7 months, range 0.3-118; 2-year survival rate 18.9%). Median follow-up of 16 surviving patients (3.5%) was 48.1 months (range 26.5-106.8). At multivariate analysis, factors independently associated with decreased survival included: poor performance status, presence of chest pain, non-epithelial cell type, visceral pleura involvement, and diffuse involvement of pleural cavity (more than one third of the cavity). On the basis of these five factors, patients were classified into three prognostic groups: a good-prognosis group (MS, 30.4 months, 95% confidence interval [CI] 17.4-42.6; 2-year survival rate 58.3%), an intermediate-prognosis group (MS, 12.3 months, 95% CI 10.7-13.8; 2-year survival rate 19.6%), and a poor-prognosis group (MS, 7.5 months, 95% CI 5.2-9.8; 2-year survival rate 7.6%) (p = 0.000001). Conclusions: This score defines three homogeneous prognostic groups and may be used to stratify patients with MPM when designing prospective clinical studies based on multimodality treatment or new biological agents.