Positron Emission Tomography/Computed Tomography for the Pleural Staging of Malignant Pleural Mesothelioma: How Accurate Is It?

Background: Careful clinical staging in patients with malignant pleural mesothelioma (MPM) is fundamental in management planning. Positron emission tomography/computed tomography (PET/CT) is increasingly recognized as an important staging modality. Objectives: The purpose of this study was to assess whether the metabolic activity of the pleural tumor detected with PET/CT correlates with specific endoscopic features and pleural distribution of the lesions as assessed by medical thoracoscopy. Methods: Consecutive patients with MPM and available PET/CT performed before thoracoscopy were separated into 2 groups, according to their standardized uptake value (SUV). Kaplan-Meier-analysis for survival was performed on groups with low and high SUV. Agreement between PET/CT and thoracoscopy evaluation was analyzed using Cohen's kappa coefficient. The Wilcoxon test was used to compare the median SUV, and the. 2 test was used to evaluate differences in endoscopic findings. Results: A total of 32 patients were included. The median maximum SUV (SUV max) was 6.1 and patients were separated into 2 groups based on this cutoff. Patients with SUV max < 6.1 had a better survival than those with SUV max >= 6.1 (p = 0.005). The comparison between PET/CT and thoracoscopy showed a fair agreement for visceral and diaphragmatic pleural involvement and moderate agreement for the presence of nodular lesions. There was a statistically significant association between median SUV max and visceral pleural involvement; nodular lesions and visceral pleural involvement were more common in the high-SUV group than in the low-SUV group (p = 0.0012 and p = 0.03, respectively). Conclusions: PET/CT data may be predictive of thoracoscopic features of MPM associated with prognosis and staging, but the correlation is moderate at best. A degree of disagreement exists between these two modalities, which supports thoracoscopy as the gold standard for assessment of local invasion in MPM. (C) 2015 S. Karger AG, Basel