Purpose: Malignant pleural mesothelioma (MPM) has a growing incidence and in spite of early diagnostic, their outcome remains dismal. The evolution of MPM is often local with rare distant metastases. There is now a sizable body of evidence that metastases could develop from circulating tumor cells (CTC) spread in blood before or during surgery. Thus, sensitive and specific detection of CTC in blood is considered as a potentially relevant predictive biomarker for patients with carcinomas. In exchange, the prognostic value of CTC in MPM has not yet been evaluated.

Indeed, the main goal for preoperative detection of CTC is to identify patients with high risk of recurrence after surgery, in order to perform more adapted therapeutic strategy. Despite several studies reported about CTC detection, methodological aspects concerning sensitivity, specificity and reproducibility have prevented a clear appraisal of their clinical impact. Thus, the aim of our study is to evaluate the presence and the prognostic value of CTC in MPM by a double approach. In our setting, cytopathological analysis of circulating non hematological cells (CNHC), of epithelial origin, isolated according to their size (ISET, Isolation by Size of Epithelial Tumor cells) along with immunomagnetic selection, identification and enumeration of circulating epithelial cells in peripheral blood (CellSearch method) is considered a promising approach.