Clinical Implications of Nonexpandable Lung in Mesothelioma

micrograph of mesothelioma, lung cancer
The presence of nonexpandable lung can be an independent predictor of mortality in mesothelioma.

The presence of nonexpandable lung can be an independent predictor of mortality in mesothelioma, according to research published in the Annals of the American Thoracic Society. Nonexpandable lung has also been linked to an increase in shortness of breath and coughing.

Researchers conducted a prospective, observational cohort study of patients with mesothelioma to determine the prevalence of nonexpandable lung and evaluate the potential association between nonexpandable lung and survival in this patient population. Participant data (n=229; 85.6% men; mean age, 64 years) were collected from a single center between 2008 and 2017. At baseline, a majority of patients were performance status 0 or 1 (27.1% and 48.5%, respectively). Among the patient population, right-sided tumors were more common than left-sided tumors (58.5% vs 41.1%).

In total, 83.8% of patients presented with pleural effusion. Of these patients, 33.3% had nonexpandable lung, and 76.6% demonstrated preserved pleural apposition over ≥ 50% of the hemithorax. Among those with nonexpandable lung, 59% of patients had a degree of nonexpandable lung smaller than the size of the overlying pleural effusion. Although left-sided tumors were more common in patients without pleural effusions, right-sided tumors were more frequently associated with both pleural effusion and underlying nonexpandable lung. The group with nonexpandable lung was composed of more men compared with the group with effusion but without nonexpandable lung and the group with no effusion (96.9% vs 81.3% vs 81.1%, respectively). Patients with nonexpandable lung more frequently reported breathlessness and cough (90.6% and 51.6%), in contrast to chest pain, which was least common in this group (34.4%).

Within the cohort, median survival time was 11.1 months; 6.6% of patients were still alive at the time of study analysis. Across all 3 groups, a similar proportion of patients died (92.3%, 93.8%, and 94.6%). Although an unadjusted survival analysis did not find any association between the presence of nonexpandable lung and increased risk for mortality, the adjusted model did associate nonexpandable lung with an increased risk for death compared with patients without nonexpandable lung (hazard ratio [HR], 1.80; 95% CI, 1.16-2.80). Multivariable models, controlling for the presence or absence of pleural effusion, indicated that the relationship between nonexpandable lung and survival was independently associated with lung expansion rather than the presence of pleural fluid. A subgroup analysis of patients with nonexpandable lung found no association between either degree of nonexpandable lung and patient survival or the presence of clinically relevant nonexpandable lung and survival (HR, 0.85; 95% CI, 0.66-1.10; P =.213 and HR, 0.78; 95% CI, 0.45-1.33; P =.362, respectively).

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Limitations to the study included the use of chest radiographs to detect nonexpandable lung, imaging based on clinical practice rather than a predefined study schedule, and the inability of investigators to ascertain symptom severity and collect serial data related to symptom evolution.

“This is the first study to describe the prevalence and clinical implications of nonexpandable lung in mesothelioma. It demonstrated that [nonexpandable lung] is a relatively common phenomenon that is associated with significant symptomatology and shorter survival,” the researchers concluded.


Bibby AC, Halford P, De Fonseka D, Morley AJ, Smith S, Maskell NA. The prevalence and clinical relevance of non-expandable lung in malignant pleural mesothelioma: A prospective, single-center cohort study of 229 patients [published online June 12, 2019]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201811-786OC