Determinants of Mortality Among US Patients Diagnosed With Malignant Pleural Mesothelioma Over the Past Decade

Background: Malignant Pleural Mesothelioma (MPM) is a primary pleural tumor with scarce prognostic data estimates given its rarity. This study aims to explore the epidemiologic and survival predictors amongst patients with MPM, extending from the largest and most recent study conducted between 1973 and 2009.

Methods: 3384 patients diagnosed with MPM between 2010 and 2017 were enrolled from the Surveillance, Epidemiology, and End Results (SEER) database. Demographics, clinical characteristics, overall mortality (OM), and cancer-specific mortality (CSM) estimates were analyzed. Multivariate Cox model was used to identify independent prognostic factors, where a hazard ratio (HR) greater than 1 denotes adverse prognostic factors.

Results: Our cohort revealed a male predominance (77.16%), with over 80% diagnosed after age 59, peaking between 60 and 79 years old (60.17%). Epithelioid mesothelioma (41.78%), non-Hispanic whites (78.13%), and diagnosis at distant stage (71.60%) were the most common subgroups in their respective categories. 365 patients (10.79%) lacked pleural effusion at diagnosis. In multivariate analyses, higher overall mortality (OM) was associated with male gender (HR = 1.24, 95% CI 1.14-1.37, p < 0.01), age >80 years (HR = 2.17, 95% CI 1.41-3.35, p < 0.01), fibrous mesothelioma (HR = 2.21, 95% CI 1.95-2.51, p < 0.01), and distant stage (HR = 1.55, 95% CI 1.34-1.81, p < 0.01). Higher cancer-specific mortality (CSM) was associated with male gender (HR = 1.25, 95% CI 1.13-1.38, p < 0.01), age >80 years (HR = 2.02, 95% CI 1.29-3.15, p < 0.01), fibrous mesothelioma (HR = 2.24, 95% CI 1.97-2.55, p < 0.01), and distant stage (HR = 1.59, 95% CI 1.36-1.87, p < 0.01). Lower OM and CSM was observed in patients who underwent any type of treatment. Nonmalignant pleural effusion, based on histology, was associated with higher CSM (HR = 1.22, 95% CI 1.05-1.4, p < 0.05).

Conclusion: Fibrous mesothelioma, older age, and distant disease were associated with increased mortality. All intervention strategies were associated with improved survival outcomes. Earlier diagnosis may improve outcomes, as available interventions are associated with lower mortality when feasible at diagnosis. The study paves the way for further prospective and retrospective studies to focus on the identification of patient subsets that may benefit from early mesothelioma screening.