Pleural thickness after neoadjuvant chemotherapy is a prognostic factor in malignant pleural mesothelioma

Definitive diagnosis of the T-component is sometimes challenging in malignant pleural mesothelioma (MPM). Pleural thickness has been reported to be a prognostic factor for MPM and is a potential T-component.

We conducted a historical cohort study of patients who underwent neoadjuvant chemotherapy (NAC) and curative-intent surgery as a multimodal treatment for MPM from January 2007 to June 2016. The maximum measurement of pleural thickness among 3 levels and the sum at each level determined using axial computed tomography imaging before and after NAC were termed as "max" and "sum," respectively. We assessed the association between pleural thickness and the primary and secondary end points of overall survival and recurrence-free survival. Survival was analyzed using the Kaplan-Meier curve, log rank test, and multivariate Cox regression model.

We enrolled 105 patients. We excluded 1 because of missing data; thus, the sample size was 104. The median follow-up period was 29.1 months with recurrence in 78 patients (70.3%) and death in 67 (60.4%). Max and sum ranged from pre (before NAC) values of 0 to 35 (median, 6.05) and 0 to 97 (median, 12.9) to post (after NAC) values of 0 to 30.8 (median, 4.25) and 0 to 67.0 (median, 9.25), respectively. Post values max and sum were associated with overall survival and recurrence-free survival. Post sum values were associated with recurrence (adjusted hazard ratio, 2.59; 95% confidence interval, 1.42-3.83) and death (adjusted hazard ratio, 2.13; 95% confidence interval, 1.16-4.52), respectively.

Pleural thickness after NAC was an independent prognostic factor in patients who underwent multimodal treatment.