The Prevalence and Clinical Relevance of Nonexpandable Lung in Malignant Pleural Mesothelioma. A Prospective, Single-Center Cohort Study of 229 Patients.

Rationale: Nonexpandable lung is a recognized phenomenon that can create management challenges in patients with mesothelioma. Its prevalence and clinical importance are unknown.Objectives: The aim of this study was to describe the prevalence of nonexpandable lung and to evaluate whether there was any association between nonexpandable lung and survival in a clinical cohort of patients with mesothelioma.Methods: This was a prospective, observational cohort study of patients with mesothelioma who were seen in a single center between March 1, 2008, and August 3, 2017. Baseline characteristics were collected at diagnosis. Serial chest radiographs were assessed for the presence of pleural effusions and nonexpandable lung (defined as a lack of lung expansion after pleural aspiration or drainage). Patients were followed until they died or were censored on March 14, 2019.Results: Of 229 patients, 192 (82.7%) had a pleural effusion at presentation, and nonexpandable lung was observed in 64 of these 192 patients (33.3%). Breathlessness and cough were more frequent in patients with pleural effusions, especially in those with underlying nonexpandable lung, whereas chest pain was more prevalent in patients without effusions. Patients with pleural effusions, both with and without underlying nonexpandable lung, were more likely to have epithelioid or early-stage disease and to receive chemotherapy than patients with no pleural effusion. Nonexpandable lung was an independent risk factor for short survival, with a hazard ratio for mortality of 1.80 (95% confidence interval, 1.16-2.80) compared with patients without nonexpandable lung. The presence of a pleural effusion did not appear to be associated with a worse prognosis compared with patients with an effusion (adjusted hazard ratio, 1.86; 95% confidence interval, 0.93-3.72).Conclusions: This is the first study to describe the prevalence and clinical implications of nonexpandable lung in mesothelioma. It demonstrates that nonexpandable lung is a relatively common phenomenon that is associated with significant symptomatology and shorter survival.Keywords: mesothelioma; nonexpandable lung; pleural effusion.