The tests and the images of the scans or X rays shows how far the disease has spread. For all type of cancer there are four stages, stage I (Initial stage), Stage II,Stage III and Stage IV are advanced stages. By knowing the stage the doctor can decide the treatment to proceed. Most of the mesothelioma patients are in advanced stages.The staging of mesothelioma in chest (that is Pleural Mesothelioma) is different from staging of mesothelioma in abdomen (peritoneal mesothelioma).
Pleural mesothelioma stages
The staging system most commonly used in the UK for pleural mesothelioma is called the International Mesothelioma Interest Group (IMIG) system.The IMIG and AJCC(The American Committee on Cancer) follow the TNM staging system.
TNM staging system (Used in AJCC)
The TNM system is the staging system most commonly used in cancer staging generally. This system has three main key pieces of information. The TNM system describes
T – The size and position of the mesothelioma primary tumour
N – Whether the mesothelioma cells have spread to nearby lymph nodes
M – Whether the mesothelioma cells have spread to other parts of the body – metastases
T,N and M categories are divided into groups of their staging.The groups are named as T group, N group and M groupand each group is divided into as many subgroups.Numbers or letters given after T, N, and M like T1, T2,Tx etc.to provide more details about each of these factors.If the cancer is in advanced the numbers will be higher.
TX: In this stage the tumour can’t be assessed for some reason.
T0: There would not be any evidence of a main tumour.
T1: Mesothelioma affects the pleura lining the chest wall on one side of the chest. It may or may not also affect the pleural tissue covering the diaphragm (the breathing muscle) or the mediastinum (the space between the lungs).
T2: Mesothelioma affects the pleura lining the chest wall on one side of the chest. It also affects the pleura coating the diaphragm. It also has grown into at least one of the following:
- The diaphragm
- The lung itself
T3: The mesothelioma has grown further but may still potentially be removed with surgery. It also has grown into at least one of the following:
- The first layer of the chest wall (called the endothoracic fascia)
- The fatty tissue in the mediastinum
- Single place in the deeper layers of the chest wall
- The surface of the pericardium (outer covering layer of the heart)
T4: The mesothelioma has grown too far to be removed completely with surgery. It also has grown into at least one of the following:
- More than 1 place in the deeper layers of the chest wall, additionally the muscle or ribs
- Any organ in the mediastinum (esophagus, trachea, thymus, blood vessels)
- The spine
- Across to the pleura on the other side of the chest
- Through the heart lining (pericardium) or into the heart itself.