The current modalities used to treat diffuse malignant pleural mesothelioma (DMPM) have not been evaluated in the setting of prospective, multi-institutional randomized trials for two reasons: DMPM is a rare disease, and there is a lack of a widely accepted and standarized staging system. Several staging systems have been proposed in an effort to categorize patients with DMPM into homogeneous groups. These efforts have been hampered by a lack of correlation between staging and survival. In our institutional experience, the Brigham staging system has been able to stratify patients with similar survival. This is an institutional experience that needs validation in a multi-institutional setting and, furthermore, in a trial based on stage-specific adjuvant therapies.