Tumor cells in pleural effusion and peripheral blood of malignant pleural mesothelioma patients

Malignant pleural mesothelioma (MPM) is an aggressive and treatment-resistant
neoplasm that is often asbestosis-induced. Patients suffering from MPM often
present with pleural effusions. Currently, no biomarker is available with an
accuracy which is clinically acceptable to either confirm or exclude the
diagnosis malignant mesothelioma, based on pleural effusion cytology.
Therefore, thoracoscopy is still the golden standard for diagnosing MPM. A
thoracoscopy is an invasive procedure associated with morbidity (amongst which
hospitalisation, pain, cardiac rhythm problems) and even with adequate tissue
it can be difficult to conclusively identify MPM. We hypothesize that the use
of a modified CellSearch enrichment method will specifically detect MPM tumor
cells in the pleural effusion of patients with MPM. By using this approach, we
aim to increase the sensitivity of fluid cytology of pleural effusion in MPM
thereby contributing to a better diagnosis of MPM and hopefully a better
outcome for patients.

Main objective is to investigate whether the use of a modified CellSearch
enrichment for the enumeration of pleural effusion tumor cells (PTCs) is able
to increase sensitivity of pleural effusion evaluation in MPM, as compared to
standard cytological analysis by the pathologist. Secondary objectives include
the investigation of the presence of circulating tumor cells (CTCs) in MPM
patients and its correlation with the presence of PTCs, the indisputable
confirmation that PTCs in patients with MPM indeed represent MPM cells, to
investigate whether there are tumor derived circulating endothelial cells
present in patients with MPM and to investigate the presence of immune cells
(e.g. regulatory T-cells and MDSC) and cytokines in MPM patients.

Prospective, non-randomized controlled trial

In all patients, except in the control patients, 3x10 mL of peripheral blood
will be drawn for circulating tumor cell (CTC), circulating endothelial cell
(CEC) and immune cell analysis.

Of all patients, 3x10 mL blood will be drawn for CTC, CEC and immune cell
analysis. In addition, pleural effusion material and, if applicable, MPM tissue
will be collected if there is residual material (which is usually the case,
since mesothelioma patients often present with large amounts of pleural
effusion fluid).