Prospective registry database of patients with malignant mesothelioma: directions for a future Japanese registry-based lung cancer study.

Background: The International Association for the Study of Lung Cancer, in collaboration with members of the International Mesothelioma Interest Group (IMIG), developed a large international database and TNM-based system to study malignant pleural mesothelioma (MPM). However, this database has some limitations since it was a retrospective study and it was based predominantly on surgical cases. The Japanese Joint Committee of Lung Cancer Registry (JJCLCR) employs a project of prospective registry database of patients in Japan with MPM in order to clarify MPM's epidemiology, current management practices, and prognosis and also to investigate the potential capabilities to target the best patients for therapy. Methods: Tumor stage is described using the 7th and 8th versions of IMIG staging system. This prospective cohort study has been conducted from April 1, 2017 to March 31, 2019. Discussion: We will analyze the data in this registry to determine the most recent outcomes and trends related to MPM treatment in Japan. The present prospective study is expected to validate the 8th version of IMIG staging system, and to investigate whether tumor thickness is a reliable T-descriptor.