The two tables below are the most common mesothelioma staging systems. The Butchart System references Stage 1 Mesothelioma, Stage 2 Mesothelioma, Stage 3 Mesothelioma, and Stage 4 Mesothelioma. Below that, the Tumor, Node, Metastases Staging System (TNM Staging System) was introduced by the International Mesothelioma Interest Group. Staging is the process of finding out how far the cancer has spread. Staging of mesothelioma is based on imaging studies such as x-rays, CT scans, and MRI scans.
Butchart Staging System (Malignant Pleural Mesothelioma)
| Stage | Location |
|---|---|
| I | Tumor confined to the ipsilateral pleura, lung, or pericardium |
| II | Tumor invading the chest wall or mediastinal structures or metastases to thoracic lymph nodes |
| III | Tumor penetrating the diaphragm to involve the peritoneum or metastases to extrathoracic lymph nodes |
| IV | Distant blood-borne metastases |
TNM Staging System (Malignant Pleural Mesothelioma)
| Stage | Location |
|---|---|
| T1a | Limited to ipsilateral parietal pleura (including mediastinal and diaphragmatic pleura), with no involvement of visceral pleura |
| T1b | Ipsilateral parietal pleura (including mediastinal and diaphragmatic pleura), with scattered foci of visceral pleural involvement |
| T2 | Ipsilateral pleural surface has at least 1 of the following:
|
| T3 | Locally advanced but resectable tumor; each ipsilateral pleural surface has at least 1 of the following:
|
| T4 | Locally advanced, technically unresectable tumor; each ipsilateral pleural surface has at least 1 of the following:
|
| NX | Regional lymph nodes not assessable |
| N0 | No regional lymph nodes metastases |
| N1 | Metastases in ipsilateral bronchopulmonary or hilar lymph nodes |
| N2 | Metastases in subcarinal or ipsilateral mediastinal lymph nodes, including ipsilateral internal mammary nodes |
| N3 | Metastases in contralateral mediastinal, contralateral internal mammary, and ipsilateral or contralateral supraclavicular lymph nodes |
| MX | Distant metastases not assessable |
| M0 | No distant metastases |
| M1 | Distant metastases present |
Understanding Mesothelioma Stages
The treatment and outlook for patients with mesothelioma largely depends on the stage (extent of spread) of their cancer. Since pleural mesothelioma occurs most frequently and has been studied the most, it is the only mesothelioma for which a staging classification exists. The staging system most often used for mesothelioma is the Butchart system. This system is based mainly on the extent of the primary tumor mass, and divides mesotheliomas into stages I through IV. Patients in Stage I of the disease have a significantly better prognosis than those with more advanced stage. However, due to the relative rarity of this mesothelioma, exact survival information based upon a stage is limited. Once malignant mesothelioma is found, more medical tests are usually performed to find out if cancer cells have spread to other parts of the body. This mesothelioma staging process is a valuable tool and helps doctors label the state of the mesothelioma cancer in order to treat it more effectively.
