Malignant mesothelioma: current status and perspective in Japan and the world

Malignant pleural mesothelioma (MPM) is associated with a poor prognosis; and to make things worse, its incidence is increasing throughout the world. Surgical management of MPM is comprised of two aspects: diagnosis and resection. Surgical biopsy with thoracoscopy provides a higher yield but a higher rate of tumor cell seeding than blind biopsy. In some surgical cases, extended surgical staging with mediastinoscopy, laparoscopy, and contralateral thoracoscopy is required for the preoperative evaluation for resectablity. There are two types of surgical resection for MPM. Pleurectomy/decortication (P/D) involves removal of as much of the visceral, parietal, and pericardial pleura and the tumor as possible without removing the underlying lung. Because P/D is less radical but less invasive compared to extrapleural pneumonectomy (EPP), it can be tolerated by poor-risk patients. EPP comprises en bloc resection of visceral, parietal, and pericardial pleura and adjacent components such as ipsilateral lung, pericardium, and diaphragm, without opening the pleural cavity. EPP was considered a highly dangerous procedure with a surgical mortality of more than 30% decades ago, but its current operative mortality/morbidity rates are 4%-9% and 60%, respectively. As macroscopic complete resection is the primary goal of surgery for MPM because of its diffuse intrapleural growth, surgical resection alone is associated with poor survival. In this context, combination therapy with surgery plus chemotherapy and/or radiotherapy is currently considered the standard treatment for patients with respectable MPM. A national survey of EPP was conducted recently in Japan, and a few multicenter clinical trials will start soon.