Cancer has always been treated by doctors in terms of stages. Each stage is used by the doctors to determine how to treat a particular cancer and ways to go about its prevention. Thus mesothelioma also has special staging systems that help the doctors to diagnose the extent of the disease in terms of particular stages. Since pleural mesothelioma is the commonest of all forms of mesothelioma, there are certain formal staging systems that are set in place to treat pleural mesothelioma. But however, since the other forms of mesothelioma are not that common, therefore there aren’t any formalized staging systems in place yet.

The Buchart System is the oldest staging system for pleural mesothelioma. This system has been based on the size of the tumor. It divides the diagnosis into four stages. This basically tracks the growth of mesothelioma from the pleural lining in the lungs to the stomach, lymph nodes, abdominal cavity and then finally the bloodstream and other main organs.

The second system is called the TNM System and is the modern staging system that is used for treating malignant mesothelioma. This, unlike the Buchart System is based on the level of growth of the tumor and the involvement of the lymph node as well. this too divides the growth of malignant mesothelioma in four stages. This system checks the metastasizing of the tumour.

The third staging system for malignant mesothelioma is called the Brigham System and is the most developed system among the three. This not only takes into consideration the involvement and extent of the lymph nodes but also other factors like whether like whether it is surgically viable and possible to operate on a malignant tumour and remove it. This quality is called resectability. Since malignant or pleural mesothelioma is rarely operable the Brigham system is not used to stage mesothelioma. It divides the disease into four stages as well. Firstly it judges as to whether the tumour is still resectable or operable at all and whether the lymph nodes are affected. The second stage decides whether the tumour is resectable while the lymph nodes have been affected. The third stage diagnoses the fact that the tumour is not operable and has metastasized while the last stage decides as to how the tumour is completely inoperable and has spread throughout the body. That stage is also called complete metastasizing.