Mesothelioma Stages

Treatment options for the treatment of Mesotheliomas are often determined by the stage of the progression that a Mesothelioma patient is in. Currently, there are three staging systems in use for Pleural Mesothelioma. Each one of these systems measures somewhat different variables. Peritoneal Mesothelioma is not staged.
The Butchart System is the oldest staging system and is the one most often used. The Butchart System is based mainly on the extent of the primary tumor mass and divides Mesotheliomas into four stages. The TNM system is more recent and considers variables of tumor in mass and spread; lymph node involvement; and metastasis. The third system for determining the stage of the Mesothelioma is the Brigham System. This system is the latest and stages the Mesothelioma according to resectability (the ability to surgically remove) and lymph node involvement.
Systems For Measuring The Stage And Progression Of Mesotheliomas
Below are the three systems and the criteria each uses to determine which stage the Mesothelioma is at.
Butchart System - A Mesothelioma Staging system which is based on the extent of the primary tumor mass

• Stage I: Mesothelioma is present in the right or left pleura and may also involve the diaphragm on the same side.
• Stage II: Mesothelioma invades the chest wall or involves the esophagus, heart, or pleura on both sides. Lymph nodes in the chest may also be involved.
• Stage III: Mesothelioma has penetrated through the diaphragm into the lining of the abdominal cavity or peritoneum. Lymph nodes beyond those in the chest may also be involved.
• Stage IV: There is evidence of metastasis or spread through the bloodstream to other organs.

TNM System - This Mesothelioma Staging system is based on an evaluation of the variables of the tumor (T); the lymph nodes (N); and if the mass is metastasis (M)

• Stage I: The Mesothelioma involves the right or left pleura and may also have spread to the lung, pericardium, or diaphragm on the same side. Lymph nodes are not involved.
• Stage II: The Mesothelioma has spread from the pleura on one side to nearby lymph nodes next to the lung on the same side. It may also have spread into the lung, pericardium, or diaphragm on the same side.
• Stage III: The Mesothelioma has moved into the chest wall, muscle, ribs, heart, esophagus, or other organs in the chest on the same side with or without spread to lymph nodes on the same side as the primary tumor.
• Stage IV: The Mesothelioma has spread into the lymph nodes in the chest on the side opposite the primary tumor, or extends to the pleura or lung on the opposite side, or directly extends into organs in the abdominal cavity or neck. Any distant metastases is included in this stage.

Brigham System - A Mesothelioma Staging system which is based on the tumor�s variables; its resectability; and nodal status.

• Stage I: The Mesothelioma tumor is Resectable and there is no lymph node involvement
• Stage II: The Mesothelioma tumor is Resectable but there is lymph node involvement
• Stage III: The Mesothelioma tumor is Unresectable, and it extends into the chest wall, the heart, or through the diaphragm and the peritoneum; there may or may not be extrathoracic lymph node involvement
• Stage IV: Along with the Mesothelioma tumor, there is distant metastatic disease

Yet Another Mesothelioma Staging System Used In The UK And Europe
The IMIG system
This Mesothelioma Staging system is based on the TNM staging system. 

The TNM system describes the extent of the primary tumour (T), the absence or presence of cancer in nearby lymph nodes (N), and the absence or presence of metastases (M) in other parts of the body. 

Once the TNM categories have been decided, the information is grouped together to give the stage. 

• Stage 1a is where the Mesothelioma affects the outer layer of the pleura around the chest wall, on one side of the chest only. It may have grown in the pleural tissue covering the diaphragm   
• Stage 1b is where the Mesothelioma has started to spread to the inner pleural layer (closest to the lungs), but remains on one side of the chest.   
• Stage 2 is where the Mesothelioma has spread to both layers of the pleura on one side of the body, and has enlarged to form a tumour mass on the pleural tissue around the lungs, or has started to spread into the diaphragm muscle or the lung tissue           
• Stage 3 is where the Mesothelioma has spread to the chest wall or the covering of the heart (pericardium), but is still potentially removable by surgery. Or it has spread to the lymph nodes on the same side of the chest         
• Stage 4 is where the Mesothelioma cannot be removed by surgery because it has spread to different parts of the chest wall, or grown through the diaphragm into the peritoneum, or to the pleura on the other side of the body, or to the chest organs, or through to the inner layer of the pericardium. Or it has spread to the lymph nodes on the other side of the chest, or above the collarbone. Or has spread to other parts of the body.

Whichever system is used for Mesothelioma Staging depends upon the doctor and/or the clinic where the patient is being treated. What is important is that the patient and the loved ones are clear about how the stages of Mesothelioma are defined and that they understand what the staging means for the progress and treatment of the Mesothelioma.